An Australian homicide expert says the Government's gun crackdown doesn't go "anywhere near" as far as theirs, and there's little evidence to suggest it'll prevent future deaths.
The Government has placed an effective freeze on sales of semi-automatic weapons, ahead of banning them almost completely when Parliament meets next month.
The legislation is expected to pass under urgency with almost unanimous support across the House, with ACT MP David Seymour likely to be the lone holdout.
"You do not defy terrorism and defend our democratic traditions by throwing out public input and parliamentary scrutiny of new laws at the first sign of trouble," he told Newshub.
"What we should be doing is respecting our democratic traditions, including parliamentary scrutiny and public input, and taking at least half of the usual time - if not the full amount of time."
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Australia took 12 days after the Port Arthur massacre of 1996 to pass its National Firearms Agreement.
"We essentially banned all semi-automatics - sporting, military, it didn't matter," said Dr Samara McPhedran of Griffith University. "They all became heavily, heavily restricted to the point of outright prohibition."
According to the police, New Zealand's law change "will bring two additional groups of semi-automatic firearms within the definition of a military style semi-automatic (MSSA) firearm". There will be "narrow exemptions for legitimate business use", the Government said on Thursday, including for pest control, farming and sporting uses.
Dr McPhedran is the director of Griffith University's Homicide Research Unit, and says the changes announced so far "do not go anywhere near" as far. But they might not need to.
"Various studies have looked for general impacts of Australia's 1996 gun law reforms... None have found evidence of a significant impact of the legislative changes on overall firearm homicide rates," she said.
But it's a difficult area to study, with mass shootings in this part of the world so rare.
"Public mass shootings did not occur in Australia before 1987 or after 1996," said Dr McPhedran.
"It is easy to say that the 1996 laws explain the absence of public shootings post-1996. However, we have no explanation for why there were none of those incidents prior to 1987, even though the laws we had throughout the 1970s and into the 1980s were extremely lax by today's standards. Semi-automatic firearms were widely available."
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Firearms researchers from the University of Otago's Department of Public Health have more faith the changes will lead to fewer deaths and decreased risk of another Christchurch-style atrocity - especially if a gun register is part of the reforms.
"A register in which all firearms are recorded would help police trace guns used in crime and to identify individuals building up an arsenal," said Dr Hera Cook.
A gun register wasn't announced on Thursday, and was rejected by then-Police Minister Paula Bennett in 2017 after being one of the recommendations made by the Law and Order Select Committee following a review of the country's gun laws.
Labour MP Kris Faafoi told The AM Show on Friday it will be looked at, and Thursday's announcement was "just the beginning".
"A register in which all firearms are recorded would help police trace guns used in crime and to identify individuals building up an arsenal," said Dr Cook.
"When guns are registered, owners then become accountable for each firearm that they own. Furthermore, registration motivates gun owners to lock up their firearms, which is a major contribution to protecting household and wider public safety."
Dr McPhedran said whatever the Government does, it needs to "do things right".
"I do appreciate that politicians are under a lot of pressure to do something quickly, but I think it's better to take time to do things right than rush into change."
Cost of a buyback scheme
The Government has also announced a gun buyback scheme, to allow owners of soon-to-be-illegal guns to hand them in. University of Waikato international law expert Al Gillespie says the Government should expand the programme to "soak up" other weapons owners no longer want, following the Christchurch attacks.
"If you put on a financial incentive, they will come back," he says - adding that it could cost more than the $100 to $200 million the Government has estimated.
"To encourage compliance, the compensation scheme needs to be fair and market-based. Lawful firearms owners have done nothing wrong and their compensation should be fair. It's going to be very expensive."
It's not known how many rifles there are in New Zealand covered by the upcoming law change. Council of Licenced Firearms Owners spokesperson Nicole McKee told The AM Show on Friday there could be as many as 400,000.
Gillespie says whatever New Zealand does, it's likely gun control advocates in other countries will look for similar action in their own countries - especially the US, where tens of thousands die every year in gun violence.
"The stronger the action, the more serious Jacinda Ardern shows the Government is taking it, and she has shown she is taking it very seriously. This kind of response you only see once in a generation, if you're lucky."