New Zealand authorities have said their country will be a safer place after owners handed in more than 50,000 guns during a buyback programme following a ban on assault weapons.

The government banned the most lethal types of semi-automatic weapons less than a month after a gunman killed 51 worshippers at two Christchurch mosques in March.

Police then launched a six-month programme to buy the newly banned weapons from owners.

The buyback ended at midnight on Friday, with gun collection events staying open late as police reported in a last-minute surge.

Provisional figures indicate 33,000 people handed in 51,000 guns, and another 5,000 weapons as part of a parallel amnesty in which owners could hand over any type of firearm without any questions being asked but without getting compensated.

New Zealand shootings: Victims of Christchurch mosque terror attacks Show all 11 1 /11 New Zealand shootings: Victims of Christchurch mosque terror attacks New Zealand shootings: Victims of Christchurch mosque terror attacks Zakaria Bhuiyan People gather hoping to find out information about Zakaria Bhuiyan who is still missing after the mosques shootings in Christchurch. David Moir/AFP New Zealand shootings: Victims of Christchurch mosque terror attacks Mucad Ibrahim Three-year-old Mucad Ibrahim, the youngest known victim of the mass shooting at two mosques in Christchurch, New Zealand, on 15 March 2019. Abdi Ibrahim via AP New Zealand shootings: Victims of Christchurch mosque terror attacks Nadeem Rasheed Nadeem Rasheed, brother of Pakistani Naeem Rashid who died alongside his son Talha Naeem, 21, who were killed in shooting at a Mosque in Christchurch, at their home town in Abbottabad, EPA New Zealand shootings: Victims of Christchurch mosque terror attacks Omar Nabi Omar Nabi speaks to the media about losing his father Haji Daoud Nabi, 71, in the mosque attack REUTERS New Zealand shootings: Victims of Christchurch mosque terror attacks Ash Mohammed Ash Mohammed, right, talks to a police officer about his father and two brothers who are missing near the Masjid Al Noor mosque AP New Zealand shootings: Victims of Christchurch mosque terror attacks Akhtar Khokhur Akhtar Khokhur, 58, shows a picture of her missing husband Mehaboobbhai Khokhar, 65. AP New Zealand shootings: Victims of Christchurch mosque terror attacks Wasseim Alsati A note is seen on a window of a door at the family home of Wasseim Alsati in Christchurch on 17 March 2019. AFP/Getty Images New Zealand shootings: Victims of Christchurch mosque terror attacks Haroon Mahmood Relatives offer condolences to nephew (centre) of Haroon Mahmood, a Pakistani citizen who was killed in Christchurch mosque shootings. AP New Zealand shootings: Victims of Christchurch mosque terror attacks Farid Ahmed Farid Ahmed (pictured) survived the Al Noor mosque shootings but his wife Husne was killed. AFP/Getty Images New Zealand shootings: Victims of Christchurch mosque terror attacks Syed Areeb Ahmed A relative shows a picture of Syed Areeb Ahmed, a Pakistani citizen who was killed the Christchurch mosque shooting. AP New Zealand shootings: Victims of Christchurch mosque terror attacks Naeem Rashid A relative looks at a picture on a mobile phone of Pakistani nationals Naeem Rashid and his son Talha Naeem (right) who died in the Christchurch shootings. AFP/Getty Images

Owners also modified another 2,700 guns to make them legally compliant, while police said they had seized a further 1,800 guns from gangs since March. Officers said they are also in the process of collecting another 1,600 weapons from gun dealers.

Police minister Stuart Nash told reporters on Saturday that criminals would find it harder to get their hands on assault weapons because they tended to steal them from lawful owners, but those weapons would now be out of circulation.

Police deputy commissioner Mike Clement thanked gun owners for doing the right thing. He acknowledged in a statement it had been “a difficult process for some people”.

Mr Nash and Mr Clement said the country is now safer than it was before the March attacks, but critics say the process was flawed and many owners have illegally stashed their firearms.

Nicole McKee, a spokeswoman for the advocacy group Council of Licenced Firearms Owners, said owners had kept about two-thirds of banned weapons because they had lost faith in the government and had not been offered adequate compensation.

“They never overcame being blamed by authorities for being somehow responsible for a heinous act of terrorism - something they would never do,” Ms McKee said in a statement.

The ban on assault weapons was strongly backed by legislators in a historic 119-1 vote after the mosque attacks. Legislators are considering further restrictions, including creating a register to track all guns.

Police figures indicate the government paid just over 100m New Zealand dollars (£50m) to compensate owners during the buyback.