An armed police officer stands guard at Parliament. Photo / Getty Images
There is cross-party support for the Government's ban on military-style semi-automatic weapons, but Labour, National and NZ First have all stymied efforts at gun law reform in the past decades.
Attempts at reform - likely in part due to a fear of losing rural votes - have been repeatedly batted away or watered down.
Having a universal firearms register and banning military-style semi-automatic (MSSA) weapons have been among the more controversial reforms that successive governments have opposed.
Firearm registration was axed in the Arms Act in 1983, which opened the door to lifetime firearms licences for "fit and proper" persons over 16 years old.
Someone with a licence could have as many firearms as they wanted. Some pistols and restricted weapons needed a special licence.
Reforms followed in 1992 after the Aramoana tragedy in 1990, when David Gray killed 13 people using a semi-automatic weapon. They included requiring a special licence for MSSAs and a permit to procure them, similar to other restricted weapons.
But a total ban on MSSAs was rejected following lobbying from gun groups, and the estimated high costs of a buy-back system.
A major push for change came with the inquiry in 1997 by retired judge Sir Thomas Thorp, which followed two shootings by police officers in 1995.
The 60 recommendations included a ban on MSSAs, limiting magazine capacity for other semi-automatics, tighter restrictions on handguns and improved security and vetting.
The buy-back scheme for the estimated 25,000 to 30,000 MSSAs was estimated to cost $21 million ($32m today).
Simon Mount, QC, who worked alongside Thorp, said lives would have been saved in the Christchurch terror attack if the inquiry's recommendations had been implemented.
But in response to the Thorp inquiry, then-Police Minister Jack Elder declined to ban MSSAs because he wanted to keep gun owners "on board", rather than "waving a big stick" by threatening to seize their guns.
In June 1999, Alliance MP Matt Robson introduced a private member's bill to establish an independent Firearms Authority to implement key recommendations of the Thorp inquiry.
But the first reading failed by a slim two-vote margin, with Labour, Alliance and NZ First voting for it, and National, United NZ, Act and several independent MPs (who had left NZ First to support the National-led Government) voting it down.
Then-Police Minister Clem Simich said in the bill's first reading that National opposed it because it would introduce its own bill.
A month later, it introduced the Arms Amendment Bill No 2, which ignored much of what Thorp recommended, but would have set up a gun register; owners that failed to register would have been fined $500.
When Labour won the election later that year, Robson thought the new Labour-Alliance Coalition would strengthen the bill with the provisions that Labour had previously supported in his own member's bill.
He said he was shocked when he was told that wouldn't happen because Labour MPs feared losing rural votes.
"We were going to implement our polices, which was implementation of the Thorp inquiry as far as possible," Robson told the Herald.
"[Then-Justice Minister] Phil Goff and [then-Police Minister] George Hawkins and I, our people met ... They said the caucus members on the select committee basically wouldn't have a bar of it.
"It was our policy. It was their policy. I was very shocked we couldn't get it through. We had the opportunity. We were the Government. There's no excuse for not doing it. "
Goff said Robson's recollection was wrong, adding through a spokeswoman that Labour never had strong support from rural voters.
Hawkins added: "I'm thinking his [Robson's] memory is a little clouded."
There were 6500 submissions on the No 2 bill at select committee, mostly opposing it on the grounds that the measures would be difficult to enforce, costly to implement, and curb individual freedom.
Hawkins said the Cabinet worked through the Thorp recommendations, and No 2 was eventually replaced in 2005 with the Arms Amendment Bill No 3.
But it was weaker than Hawkins personally wanted.
"I was very disappointed, but when you're only one voice in Cabinet, you are bound by what the Cabinet decides," Hawkins said.
"Hindsight has made people think differently."
No 3 aimed at complying with a United Nations convention on manufacturing and trafficking illegal firearms. It proposed three new offences, but did not require universal registration of firearms.
It took eight years - and a change of Government - for the select committee to report back on the bill, and when it did, Opposition Labour and Green MPs supported it as it would see New Zealand accede to UN protocols.
But a majority of the committee - National and NZ First MPs - opposed it because it was apparently about to be usurped by a new bill - the Arms Amendment Bill No 4.
No 4 was never introduced.
In March 2016, the New Zealand Police seized 14 illegally owned firearms from a home in Takanini, triggering a cross-party select committee inquiry into how criminals and gangs were getting high-calibre weapons.
The committee reported back the following year with 20 recommendations. The only dissenting voice was NZ First MP Ron Mark, who said the recommendations would restrict "legitimate ownership of legally-held firearms" and would do nothing to stop criminals from committing offences with illicit firearms.
A majority of committee members were National MPs, but the following year, then-Police Minister Paula Bennett rejected 12 of the 20 recommendations, a move applauded by Federated Farmers.
One of the dropped recommendations was to investigate a new category of restricted semi-automatic rifle and shotgun.
Bennett said many of the recommendations would unduly affect legal firearm users.
Among the accepted recommendations were bringing in firearm prohibition orders, reviewing penalties, and clarifying that gang members were not eligible to legally possess firearms.
Bennett also added two more, including for police to consult better with gun-owners, opening her to criticism that she was bowing to lobbyists.
Labour's police spokesman Stuart Nash supported Bennett's decision "100 per cent", even though he was on the committee that endorsed all the recommendations.
Act leader David Seymour also backed Bennett, saying the committee's recommendations went "far beyond" targeting illegal gun possession.
Soon after becoming Police Minister 18 months ago, Nash set up a committee to review gun laws. National's police spokesman Chris Bishop has also been consulting the public on gun laws. Those processes are ongoing.
Following Friday's terrorist attack, political attitudes have done an about-face.
"After 1pm on the 15th of March, our world changed forever and so will some of our laws," said NZ First leader Winston Peters, whose party has been seen as a strong advocate of legal gun users.
Nash, when asked about his full support for National rejecting most of the 2017 recommendations, said: "The world has changed."
It's understood a NZDF aircraft and multiple helicopters are involved.