"On 15 March our history changed forever. Now, our laws will too. We are announcing action today on behalf of all New Zealanders to strengthen our gun laws and make our country a safer place," Ardern said.
"Cabinet agreed to overhaul the law when it met on Monday, 72 hours after the horrific terrorism act in Christchurch. Now, six days after this attack, we are announcing a ban on all military style semi-automatics (MSSA) and assault rifles in New Zealand.
"Related parts used to convert these guns into MSSAs are also being banned, along with all high-capacity magazines.
"An amnesty will be put in place for weapons to be handed in, and Cabinet has directed officials to develop a buyback scheme. Further details will be announced on the buyback in due course.
"All semi-automatic weapons used during the terrorist attack on Friday 15 March will be banned.
"Legislation to give effect to the ban will be introduced when Parliament sits in the first week of April. We will provide a short, sharp Select Committee process for feedback on the technical aspects of the changes. We are looking to progress the amendments to this legislation under urgency and expect these amendments to the Arms Act to be passed within the next session of Parliament," Jacinda Ardern said.
The Opposition backs the ban and National Party Simon Bridges says the terrorist attack in Christchurch last week has changed New Zealand as a nation.
"National has been clear since this devastating attack that we support changes to our regime and that we will work constructively with the Government.
"We agree that the public doesn't need access to military style semi-automatic weapons. National supports them being banned along with assault rifles.
"We also support the Government's proposals to limit the access to other high powered semi-automatic weapons and ammunition," he said.
Federated Farmers said it supported the Government's intention to toughen firearms regulations.
"This will not be popular among some of our members but after a week of intense debate and careful consideration by our elected representatives and staff, we believe this is the only practicable solution," spokesperson Miles Anderson said.
The lobby group agreed there was no need for military style semiautomatic rifles in general public ownership.
It also also supported the move to prohibit general access to, and possession of, detachable large capacity magazines for semiautomatic firearms.
"We're pleased farmers are still going to have access to sporting semiautomatic rimfire rifles, such as the .22 long rifle, and sporting semiautomatic shotguns with limited magazine capacity," he said.
These are needed for control of small, mobile pest species often found in groups "where quick follow-up shots is important for efficient, fast and humane destruction of these pests".
But the group said there was a "limited need" for centrefire semiautomatic firearms with large capacity magazines for professional pest management, but this access should be controlled by the kind of police checks, registration of individual firearms and the increased security requirements that currently apply to E category licences.
"The surrender or destruction of firearms that don't meet the new controls will be disappointing to many farmers, and others," Anderson said,
"But a clampdown is the responsible path to take to try to ensure we're never witness to this kind of tragedy on our shores again."
