Christchurch, New Zealand (CNN) In the wake of last Friday's attacks in Christchurch in which 50 people were killed , New Zealand faces a defining moment on the availability of guns in society.

Prime Minister Jacinda Ardern has pledged tough measures to limit their circulation -- but in a country with a strong hunting tradition, where there is roughly one gun for every four people, it will be no easy path.

As Ardern herself said at the weekend, there have been unsuccessful attempts to tighten gun control in the past -- in 2005, 2012 and again two years ago. For previous governments, it has not been a priority -- because while having relatively high gun ownership, New Zealand has until now had relatively few gun-related deaths.

According to figures compiled by the University of Sydney , New Zealand had 0.17 gun-related homicides per 100,000 people in 2015. This is in contrast to the United States, which had 11 deaths per 100,000 people in 2015, according to a report from the US Centers for Disease Control and Prevention.

Those figures will look very different in 2019 -- and for Ardern's Labour-led government, gun legislation is now the highest political priority.

The government certainly has public momentum behind it. Many New Zealanders are shocked that someone could acquire so many powerful weapons legally.

The alleged perpetrator of Friday's attacks, 28-year-old Brenton Tarrant, possessed a "Category A" gun license, giving him the right to buy semi-automatic weapons.

Tarrant had two semi-automatic weapons and two shotguns among his arsenal.

"That will give you an indication of why we need to change our gun laws," Ardern said at the weekend.

Photos: In photos: World reacts to New Zealand terror attacks A man passes a makeshift memorial for the New Zealand victims at the Great Mosque of Paris on Friday, March 22. Hide Caption 1 of 76 Photos: In photos: World reacts to New Zealand terror attacks Muslim men pray in Hagley Park near Al Noor mosque in Christchurch, New Zealand, on Saturday, March 23. Most of the victims in the terror attacks died at that mosque. Hide Caption 2 of 76 Photos: In photos: World reacts to New Zealand terror attacks Muslims pray during Friday prayers at Hagley Park in Christchurch on March 22. Hide Caption 3 of 76 Photos: In photos: World reacts to New Zealand terror attacks Mourners carry a body at Memorial Park Cemetery in Christchurch on March 22 as funerals continued a week after the deadly attacks. Hide Caption 4 of 76 Photos: In photos: World reacts to New Zealand terror attacks The sun sets behind Ponsonby Masjid Mosque during an open service for all religions on March 22 in Auckland, New Zealand's largest city. Hide Caption 5 of 76 Photos: In photos: World reacts to New Zealand terror attacks Mourners embrace following a burial ceremony at Memorial Park Cemetery in Christchurch on March 22. Hide Caption 6 of 76 Photos: In photos: World reacts to New Zealand terror attacks Friday prayers and two minutes of silence are observed for victims at Hagley Park in Christchurch on March 22. Hide Caption 7 of 76 Photos: In photos: World reacts to New Zealand terror attacks Residents gather for a call to prayer at Masjid E Umar Mosque in Auckland on March 22. Hide Caption 8 of 76 Photos: In photos: World reacts to New Zealand terror attacks Zaid Mustafa, second left, son and brother of victims from the mosque attacks, is welcomed at Friday prayers at Hagley Park in Christchurch on March 22. Hide Caption 9 of 76 Photos: In photos: World reacts to New Zealand terror attacks A mourner holds a New Zealand flag during a mass burial at Memorial Park Cemetery in Christchurch on March 22. Hide Caption 10 of 76 Photos: In photos: World reacts to New Zealand terror attacks New Zealand Prime Minister Jacinda Ardern leaves Friday prayers at Hagley Park in Christchurch on March 22. Hide Caption 11 of 76 Photos: In photos: World reacts to New Zealand terror attacks A woman attends Friday prayers at the Ponsonby Masjid Mosque in Auckland, New Zealand. Hide Caption 12 of 76 Photos: In photos: World reacts to New Zealand terror attacks New Zealand All Blacks rugby player Sonny Bill Williams greets members of the Muslim community after attending Friday prayers near Al Noor mosque in Christchurch, New Zealand. Hide Caption 13 of 76 Photos: In photos: World reacts to New Zealand terror attacks An armed police officer patrols near Al Noor mosque in Christchurch. Hide Caption 14 of 76 Photos: In photos: World reacts to New Zealand terror attacks People gather at the Ponsonby Masjid Mosque during an open service to all religions Friday in Auckland, New Zealand. Hide Caption 15 of 76 Photos: In photos: World reacts to New Zealand terror attacks A police officer stands guard at the burial service for a victim of the mosque shootings in Christchurch, New Zealand. Hide Caption 16 of 76 Photos: In photos: World reacts to New Zealand terror attacks Visitors look on as Muslims attend Friday prayers in a park near Al Noor mosque in Christchurch, New Zealand. Hide Caption 17 of 76 Photos: In photos: World reacts to New Zealand terror attacks People gather at the Ponsonby Masjid Mosque during an open service to all religions Friday in Auckland, New Zealand. Hide Caption 18 of 76 Photos: In photos: World reacts to New Zealand terror attacks A coffin containing the body of a victim of the Christchurch mosque attacks is carried for burial at Memorial Park Cemetery on Friday in Christchurch, New Zealand. Hide Caption 19 of 76 Photos: In photos: World reacts to New Zealand terror attacks Police inspect bags of the guests arriving at the Ponsonby Masjid Mosque during an open service to all religions Friday in Auckland, New Zealand. Hide Caption 20 of 76 Photos: In photos: World reacts to New Zealand terror attacks Visitors look on as Muslims attend Friday prayers in a park near Al Noor mosque. Hide Caption 21 of 76 Photos: In photos: World reacts to New Zealand terror attacks Artists paint a mural "Peace, Unity, Hello Brother" for the New Zealand shooting victims. The words an elderly Muslim reportedly used to greet a white supremacist gunman have become Christchurch's answer to hate. Hide Caption 22 of 76 Photos: In photos: World reacts to New Zealand terror attacks An armed policeman walks alongside a fence at Memorial Park Cemetery as a funeral takes place for two of the victims of the Christchurch attack on March 20 in Christchurch. Hide Caption 23 of 76 Photos: In photos: World reacts to New Zealand terror attacks Zaid Mustafa (in wheelchair), who was wounded in the attack on two mosques in Christchurch, New Zealand, attends the funeral of his slain father, Khalid Mustafa and brother Hamza Mustafa at the Memorial Park Cemetery in Christchurch on March 20. Hide Caption 24 of 76 Photos: In photos: World reacts to New Zealand terror attacks Women mourn at Memorial Park Cemetery on March 20 after attending the funerals of two victims of the Christchurch terrorist attack. Hide Caption 25 of 76 Photos: In photos: World reacts to New Zealand terror attacks A mourner in a wheelchair leaves Memorial Park Cemetery on March 20 after attending a funeral for victims killed in the mosque massacre in Christchurch, New Zealand. A Syrian refugee and his son were buried in the first funerals for those killed in the attack as New Zealanders braced for days of emotional farewells following the mass slayings. Hide Caption 26 of 76 Photos: In photos: World reacts to New Zealand terror attacks Mourners carry the coffin of a shooting victim during a funeral at the Memorial Park Cemetery in Christchurch on Wednesday, March 20. Hundreds of mourners gathered for the first funerals of those killed as New Zealanders braced for days of emotional farewells. Hide Caption 27 of 76 Photos: In photos: World reacts to New Zealand terror attacks People mourn at a makeshift memorial site near the Al Noor mosque in Christchurch, New Zealand, on Tuesday, March 19. Streets near the hospital that had been closed for four days reopened to traffic as relatives and friends of the victims of last week's mass shootings continued to stream in from around the world. Hide Caption 28 of 76 Photos: In photos: World reacts to New Zealand terror attacks Mufti Zeeyad Ravat, right, a Muslim leader from Melbourne, leads a prayer at the Deans Avenue memorial, near the Al Noor mosque in Christchurch, New Zealand, on Tuesday, March 19. Hide Caption 29 of 76 Photos: In photos: World reacts to New Zealand terror attacks Floral tributes to those who were gunned down at the two mosques are seen against a wall bordering the Botanical Garden in Christchurch on March 19, 2019. New Zealand Prime Minister Jacinda Ardern vowed never to utter the name of the gunman as she opened a sombre session of parliament with an evocative "as-salaam alaikum" message of peace to Muslims. Hide Caption 30 of 76 Photos: In photos: World reacts to New Zealand terror attacks A photo tribute for Christchurch mosque shooting victim Tariq Omar lies amid mounds of flowers across the road from the Al Noor mosque in Christchurch, New Zealand Tuesday, March 19. Hide Caption 31 of 76 Photos: In photos: World reacts to New Zealand terror attacks A mourner takes a picture of candles commemorating victims of Friday's shooting, outside the Al Noor mosque in Christchurch, New Zealand, Monday, March 18. Three days after the attack, New Zealand's deadliest shooting in modern history, relatives were anxiously waiting for word on when they can bury their loved ones. Hide Caption 32 of 76 Photos: In photos: World reacts to New Zealand terror attacks Women weep as they comfort each other during a vigil near the Masjid Al Noor mosque in Christchurch, New Zealand, on Monday, March 18. Hide Caption 33 of 76 Photos: In photos: World reacts to New Zealand terror attacks Fifty pairs of white shoes have been laid in front of All Souls Anglican Church in honor of victims who lost their lives on March 18, in Christchurch, New Zealand. Hide Caption 34 of 76 Photos: In photos: World reacts to New Zealand terror attacks Vice President of Turkey, Fuat Oktay (right), and Minister of Foreign Affairs of Turkey, Mevlut Cavusoglu, lay flowers during their March 18 visit to Al Noor mosque, which was targeted in Friday's twin terror attacks in Christchurch, New Zealand. Hide Caption 35 of 76 Photos: In photos: World reacts to New Zealand terror attacks Pope Francis reads his message during the Angelus noon prayer from the window of his studio overlooking St. Peter's Square at the Vatican, Sunday, March 17. Francis has offered prayers for "our Muslim brothers" killed in the attack against two mosques in Christchurch, New Zealand. Hide Caption 36 of 76 Photos: In photos: World reacts to New Zealand terror attacks A relative weeps while showing the picture of Sohail Shahid, a Pakistani citizen who was killed in the Christchurch mosque shootings, on his cell phone outside his home in Lahore, Pakistan, Sunday, March 17. Pakistan's foreign ministry spokesman says three more Pakistanis have been identified among the dead, increasing the number of Pakistanis to nine killed in the mass shootings at two mosques in the New Zealand city of Christchurch. Hide Caption 37 of 76 Photos: In photos: World reacts to New Zealand terror attacks Residents cry after leaving flowers in tribute to victims in Christchurch on March 17. Hide Caption 38 of 76 Photos: In photos: World reacts to New Zealand terror attacks The Kuwait Towers display the flag of New Zealand in solidarity with the victims of the Christchurch mosque attacks in Kuwait City on March 17. Hide Caption 39 of 76 Photos: In photos: World reacts to New Zealand terror attacks Women embrace near Masjid Al Noor mosque in Christchurch, New Zealand, on March 17. Hide Caption 40 of 76 Photos: In photos: World reacts to New Zealand terror attacks Local surfers and surfers competing in the Sydney Surf Pro participate in a paddle-out, wreath laying and observe a minute of silence to remember victims of the Christchurch mosque attacks at Manly Beach on March 17 in Sydney, Australia. Hide Caption 41 of 76 Photos: In photos: World reacts to New Zealand terror attacks Catherine, Duchess of Cambridge, and Prince William, Duke of Cambridge, observe a moment of silence for the victims of the attacks in Christchurch during the 1st Battalion Irish Guards St. Patrick's Day Parade at Cavalry Barracks on March 17. Hide Caption 42 of 76 Photos: In photos: World reacts to New Zealand terror attacks People light candles next to the Botanic Gardens in Christchurch on March 17. Hide Caption 43 of 76 Photos: In photos: World reacts to New Zealand terror attacks The Warriors observe a moments silence for the victims of the Christchurch mosque shootings during the round 1 NRL match between the New Zealand Warriors and the Canterbury Bulldogs at Mt Smart Stadium on Saturday, March 16, in Auckland, New Zealand. Phil Walter/Getty Images Hide Caption 44 of 76 Photos: In photos: World reacts to New Zealand terror attacks People hold a vigil at Washington Square Park in New York on March 16. Hide Caption 45 of 76 Photos: In photos: World reacts to New Zealand terror attacks Mourners pay their respects at a makeshift memorial near the Al Noor mosque in Christchurch, New Zealand, on March 16. Hide Caption 46 of 76 Photos: In photos: World reacts to New Zealand terror attacks Crowds gather on Takapuna Beach in Auckland, New Zealand, on March 16 for a vigil for the victims of the Christchurch attacks. Hide Caption 47 of 76 Photos: In photos: World reacts to New Zealand terror attacks A man cries during a demonstration in Istanbul on March 16. Hide Caption 48 of 76 Photos: In photos: World reacts to New Zealand terror attacks Indian Muslims at Siddi Sayed Jaali in Ahmedabad pray March 16 in solidarity with the Christchurch victims. Hide Caption 49 of 76 Photos: In photos: World reacts to New Zealand terror attacks A woman visits a makeshift memorial in Christchurch. Hide Caption 50 of 76 Photos: In photos: World reacts to New Zealand terror attacks A Pakistani man embraces the father of Syed Areeb Ahmed (right), reportedly gunned down in the New Zealand massacre, in Karachi on March 16. Hide Caption 51 of 76 Photos: In photos: World reacts to New Zealand terror attacks A silver fern is projected onto the sails of the Sydney Opera House on March 16 in memory of the victims of the New Zealand mosque attacks. Hide Caption 52 of 76 Photos: In photos: World reacts to New Zealand terror attacks A candlelight prayer is held outside the State Library of Victoria, in Australia, on Saturday, March 16. Hide Caption 53 of 76 Photos: In photos: World reacts to New Zealand terror attacks People take part in a memorial to the Christchurch victims in central Grozny, in the Russian region of Chechnya. Hide Caption 54 of 76 Photos: In photos: World reacts to New Zealand terror attacks The colors of the New Zealand flag are projected onto the historic Old Bridge over the Neretva River in Mostar, Bosnia-Herzigovina, to commemorate the victims of the deadly mosque attacks in Christchurch. Hide Caption 55 of 76 Photos: In photos: World reacts to New Zealand terror attacks Najeeba Syeed, left, hugs Judy Gilliland at the Islamic Center of Southern California in Los Angeles, where people of all faiths came together in prayer March 16. Hide Caption 56 of 76 Photos: In photos: World reacts to New Zealand terror attacks People perform a funeral prayer in absentia on March 16 in Ankara, Turkey. Hide Caption 57 of 76 Photos: In photos: World reacts to New Zealand terror attacks New Zealand Prime Minister Jacinda Ardern meets with Muslim community representatives March 16 in Christchurch. Hide Caption 58 of 76 Photos: In photos: World reacts to New Zealand terror attacks People mourn March 16 at Hagley College in Christchurch. Hide Caption 59 of 76 Photos: In photos: World reacts to New Zealand terror attacks A woman lays flowers at Deans Avenue near Al Noor Mosque in Christchurch on March 16. More than 40 people were killed at that mosque, according to authorities Hide Caption 60 of 76 Photos: In photos: World reacts to New Zealand terror attacks People pray for the victims at the al-Aqsa Mosque on Friday, March 15, in Jerusalem. Hide Caption 61 of 76 Photos: In photos: World reacts to New Zealand terror attacks The lights of the Eiffel Tower in Paris are shut off early on March 16 in tribute to the victims of the Christchurch terrorist attack. Hide Caption 62 of 76 Photos: In photos: World reacts to New Zealand terror attacks Nayab Khan, 22, cries at a vigil to mourn the victims of the Christchurch mosque attacks in New Zealand, at the University of Pennsylvania in Philadelphia on Friday, March 15. Hide Caption 63 of 76 Photos: In photos: World reacts to New Zealand terror attacks New Zealand's national flag is flown at half-staff on a Parliament building in the capital, Wellington, on March 15. Hide Caption 64 of 76 Photos: In photos: World reacts to New Zealand terror attacks Omar Nabi, standing at the district court in Christchurch, speaks to the media about losing his father, Haji Daoud, in the mosque attacks. Hide Caption 65 of 76 Photos: In photos: World reacts to New Zealand terror attacks Demonstrators chant slogans during a protest in Istanbul. Hide Caption 66 of 76 Photos: In photos: World reacts to New Zealand terror attacks A police officer stands guard as Muslims pray in Dhaka, Bangladesh, on March 15. Hide Caption 67 of 76 Photos: In photos: World reacts to New Zealand terror attacks Young demonstrators hold banners from the multifaith group Turn to Love during a vigil at the New Zealand House in London. Hide Caption 68 of 76 Photos: In photos: World reacts to New Zealand terror attacks Police officers sit in their vehicle outside the Al Aqsa Islamic Society mosque in Philadelphia on March 15. Many cities bumped up their police presence outside of mosques. Hide Caption 69 of 76 Photos: In photos: World reacts to New Zealand terror attacks Delegates stand during a minute of silence that was observed at the United Nations Human Rights Council in Geneva, Switzerland. Hide Caption 70 of 76 Photos: In photos: World reacts to New Zealand terror attacks Players from the Australian basketball team Melbourne United observe a moment of silence before a game in Perth, Australia, on March 15. Hide Caption 71 of 76 Photos: In photos: World reacts to New Zealand terror attacks Worshippers leave the Great Mosque of Paris after Friday prayers. Hide Caption 72 of 76 Photos: In photos: World reacts to New Zealand terror attacks A flag flies at half-staff in London on March 15. Hide Caption 73 of 76 Photos: In photos: World reacts to New Zealand terror attacks This wreath was placed by Labour Party leader Jeremy Corbyn outside the New Zealand High Commission in London. "In their memory, let us build a world of dignity and respect," he said on the note. Hide Caption 74 of 76 Photos: In photos: World reacts to New Zealand terror attacks The Canadian flag flies at half-staff on the Peace Tower in Ottawa. Hide Caption 75 of 76 Photos: In photos: World reacts to New Zealand terror attacks The Chiefs and Hurricanes gather together to remember the victims ahead of a professional rugby match in Hamilton, New Zealand. Hide Caption 76 of 76

Obtaining a license involves police background checks and firearms safety. But they are rarely refused, according to the latest figures. In 2017, of the 43,509 firearms license applications submitted, just 188 applications were declined. And a Category A license allows the holder to obtain any number of sporting-type rifles and shotguns. You don't need one license per weapon.

Visitors to New Zealand can apply for a firearms license that "will let you shoot for hunting or competition in New Zealand for up to a year," according to police.

Some variants of the AR-15, which has been used in several mass shootings in the US, can be legally obtained by Category A holders in New Zealand. The power of such a weapon can then be enhanced by adding a high-capacity magazine. A police report two years ago warned that such adaptations opened the way to "criminal harm" and noted that "purchase of high-capacity magazines is unregulated and does not require a firearms licence."

One such adapted weapon was used in the murder of two people in New Zealand in 2017.

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New Zealand's patchwork of gun laws have also allowed the import of semi-automatic rifles, of which there are about 15,000 legally in circulation, according to police estimates. The lack of a national register of gun ownership makes such estimates more difficult.

The New Zealand Police Association has long called for reform of the Arms Act and tougher measures to close loopholes on acquiring semi-automatic weapons.

Its president, Chris Cahill, said at the weekend: "There is no place in the upcoming debate for the radical gun lobby which has made its presence felt in previous attempts to make our country safer. We have seen what happens in the United States when gun radicals are involved. Nothing. That is not good enough for New Zealand."

Cahill also makes the point that Tarrant would have found it more difficult to acquire such powerful weapons in his native Australia, which had its "Christchurch moment" back in 1996.

That was the year of the Port Arthur massacre, when a lone gunman with a semi-automatic weapon killed 35 people and wounded more than 20, using an AR-15 with a 30-round magazine. The Australian government moved swiftly to outlaw such weapons after the attack. Rapid-fire rifles and shotguns were banned, gun owner licensing was tightened and remaining firearms were registered to uniform national standards. An ambitious government-funded gun buyback program was introduced.

The Dunblane massacre -- also in 1996 -- when 16 schoolchildren and their teacher were murdered in Scotland brought about tighter gun controls in the UK. But it took several years for the number of criminal offenses involving guns to begin to fall.

New Zealand now faces a similar watershed moment.

David Small, a lawyer and professor at Canterbury University in Christchurch, says it's a question of what's reasonable in a country where guns are important for hunting and pest control. "There is nothing reasonable about owning a gun whose main purpose is self-defense," he says, "and in New Zealand there is no constitutional right to bear arms. To introduce tighter gun control is not going to infringe basic liberties."

Even with public sentiment behind her, Ardern's government still faces a daunting challenge in devising watertight legislation that begins to regulate the availability of guns in New Zealand.

Speaking to CNN on Monday, Philip Alper, editor of GunPolicy.org, a Australian website that tracks armed violence, firearm law and gun control, said that the New Zealand gun lobby will likely resist any attempt to adopt tighter controls.

According to Alper, there have been four inquiries into possible changes to New Zealand's gun laws during the past 22 years -- and the gun lobby has stymied every one of them.

"The gun lobby is already talking about consultation, no knee jerk reactions. 'Come out to the gun range and see were good people,' and that has the effect of watering down every gun law that's been tested," says Alper.

One possible new route would be the introduction of a buy-back program, as well as closing loopholes that allow the import and adaptation of powerful guns, says Small.

"The time and place will never be better," he told CNN. "No opposition party has anything to gain by opposing such legislation."

Former New Zealand premier Helen Clarke agrees.

Gun laws need improving, she said, and "I would be surprised if the New Zealand Parliament didn't accept that challenge head-on to strengthen the law."

Former Australian Prime Minister John Howard, who passed through Australia's strict gun control laws after the Port Arthur massacre, said Monday that he believes there would be "universal acceptance across the political divide" for gun control reform.

"Bear in mind getting anything accepted in New Zealand which is not a federation and only has a lower house of parliament, is a fairly simple issue if there is political will. I can't imagine after this that there won't be political will to bring their laws up to date," Howard said.

Correction: A previous version of this story incorrectly spelled New Zealand Prime Minister Jacinda Ardern's name. It has now been updated. This story has also been updated with the correct homicide rate for New Zealand in 2015.