New Zealand Prime Minister Jacinda Ardern announced the "first tranche" to reforms on gun laws - beginning with the immediate ban on the sale of semi-automatic and 'assault' rifles, six days after attacks on two mosques in Christchurch left 50 people dead. Notably, accused gunman Brenton Tarrant - specifically hoped his attack would lead to the restriction of gun rights.

"On 15 March, our history changed forever. Now, our laws will too," said Ardern. "We are announcing action today on behalf of all New Zealanders to strengthen our gun laws and make our country a safer place."

"The effect of this will mean that no one will be able to buy these weapons without a permit to procure from the police. I can assure people that there is no point in applying for such a permit," she said, adding "In short, every semi-automatic weapon used in the terrorist attack on Friday will be banned in this country."

The ban will apply to all firearms currently defined as "Military Style" or "Semi-Automatic" (MSSA), defined as a semi-automatic firearm - including shotguns - capable of being used with a detachable magazine that holds more than five rounds.

National Rifle Association of New Zealand president Malcolm Dodson holding a bolt-action rifle not subject to the new ban. (ROBERT KITCHIN/STUFF)

Guns which are not affected by the ban include semi-automatic .22 caliber rimfire firearms with a magazine holding no more than 10 rounds, as well as semi-automatic and pump-action shotguns with a non-detachable tubular magazine holding no more than five rounds.

🚨🚨OFFICIAL NEW ZEALAND GUN BAN Q&A sent out to reporters. I snagged this from @callapilla. She chopped it up into multiple tweets and I thought that was dumb. Here it is all at once. pic.twitter.com/dhiwtu2orc — Nick Monroe (@nickmon1112) March 21, 2019

Ardern also announced a gun buyback scheme that will cost between NZ$100 million and $200 million (between US$69 million and $139 million), depending on the number of weapons received.

Anyone who keeps their guns after an amnesty period which has yet to be announced will face fines of up to $4,000 and three years in jail - which is less jail time than a New Zealand resident could receive for downloading or sharing a video of the Christchurch attacks.

As far as "Tranche two," Ardern said "There is more to be done and tranche two will look at issues around licensing, issues around registration, issues around storage. There are a range of other amendments that we believe do need to be made and that will be the second tranche of reforms yet to come."

Currently in New Zealand:

· There are 245,000 firearms licences

· Of these, 7,500 are E-Category licences; and 485 are dealer licenses

· There are 13,500 firearms which require the owner to have an E-Cat licence, this is effectively the known number of MSSAs before today’s changes

· The total number of firearms in New Zealand is estimated to be 1.2-1.5 million

That said, Ardern told reporters that she has no idea how many assault rifles are in New Zealand. The police minister followed up, saying: "It’s part of the problem. The prime minister gave a figure for the buyback [$100m - $200m], the reason there’s such a large gap is we have no idea."