New Zealand gun sales reportedly increase after Christchurch attacks

Sales of guns in New Zealand have reportedly increased after a government vow to change firearm laws following Christchurch's deadly terror attack.

But Prime Minister Jacinda Ardern says the facts are still being checked and she "cannot be deterred".

Ms Ardern announced her government would be tightening laws after it was found Australian Brenton Tarrant, who is alleged to have killed 50 people at two mosques in Christchurch on Friday, possessed five guns.

Gun stores were busy over the weekend, with an Auckland shop owner reporting significant increases in sales of semi-automatics while talk emerged of "panic buying", according to Newsroom.

Ms Ardern said the claims were being looked into but were not yet verified.

"I want to get to the bottom of whether or not that has occurred," she said.

She added she would not back down either way.

"We cannot be deterred from the work we need to do on our gun laws in New Zealand. They need to change, regardless of what activity may or may not have happened with gun retailers."

The gunman obtained a licence in November 2017 allowing him to buy the weapons, including two semi-automatic rifles, beginning the following month.

The weapons are understood have have been illegally modified and the issue, along with the availability of semi-automatics are now being swiftly reviewed.