Gun safety experts expect swift clampdowns on gun ownership after Prime Minister Jacinda Ardern pledged to change the country's near 30-year-old gun laws.
Close to a quarter of a million people in New Zealand hold firearm licences and only military-style semi-automatic guns need to be registered, leaving the majority un-accounted for by authorities.
Exactly what will change is not yet known. However, gun safety advocates have said banning semi-automatic firearms and registering all guns would be a good start.
Police Association president Chris Cahill said semi-automatic weapons needed to be banned.
"We know how easy it is to get firearms in New Zealand and while today and the next few days is the time to look after the welfare of the victims and their families, clearly we need to have a look at firearms law in New Zealand," Mr Cahill said.
He said there also needed to be a register of all guns and who owned them.
"If someone was building up a cache of weapons and there was some alarms around that, it would be something that could be followed up. But as it stands now, we have no idea who's buying weapons and where they're keeping them or how many they have in New Zealand."
The gunman responsible for the terrorist attacks on mosques on Christchurch on Friday held a standard firearms licence that allowed him to own limited power semi-automatic weapons.
Police said it may have been possible for him to have bought his firearms legally and then altered them, to turn them in to semi-automatic weapons.
Coalition of Licenced Firearm Owners secretary Nicole McKee said there was a stringent vetting process for firearm licenses that included interviews with referees.
She told Guyon Espiner on Morning Report that she didn't believe military style semi-automatic weapons should be banned.
"We have several legitimate uses for them in this country, we have them for sporting uses, we have them for on rural properties, we have work places that use them for culling. So there's actually quite a number of reasons that we have them."
Even so, she said changes may needed to be made to ensure the wrong people did not access firearms in the future.
"We have the ability here in New Zealand to continue to treat the licence holder as fit and proper and maybe the issue needs to be how did this guy get his licence? And if the process there needs serious looking at and perhaps amending."
Ms McKee said the rifle association did not want to see ill-considered legislative changes.
"What we don't want to see is knee-jerk legislative changes because they will always have unintended consequences. We need to ensure there is well considered and well-funded investigations to prevent this occurring in the future."
However, a lawyer specialising in firearms legislation said there are too many loopholes in the current vetting process.
Nicholas Taylor told Morning Report to get category A licence an applicant needed to put forward two people as referees: someone with whom they lived and another who had known them for a long period of time.
Police were then able to vet those referees, Mr Taylor said.
The application forms have more psychometric data in than ever, he said.
"However what they don't do, is they don't look at, or investigate anything further beyond that, unless it's highlighted by one of those referees.
"Now if the referees are in potential cahoots with the person ... that's where it would end."
Police also need more resources, he said.
"Give police the resources to look at someone's online presence now, because that's just not done, this person had a very large and extensive online presence which just wasn't examined."
While semi-automatic guns were over a hundred year's old, it was easy now to adapt them into military style weapons, he said.
"Because of its form, it can be updated with various accessories and those accessories, such as 30 round magazines, move it from a standard firearms licence into what we call a MSSA [military-style semi automatic]."
Gun policy expert and University of Sydney Associate professor Philip Alpers said someone with a standard firearms license was entitled to own as many entry level firearms as they would like to.
He said he was not surprised to learn the terror attacks were likely perpetrated with legally held weapons.
"We're all assuming that he legally owned those firearms. I wasn't at all surprised by that because most of the victims of mass shootings in Australia and New Zealand have been shot and killed by lawful firearm owners holding legally held guns."
He said gun laws could change in a matter of days if there was the political and public will, as in Australia after the Port Arthur massacre in 1996 when gun laws changed in 12 days.
"You don't have nine jurisdictions to wrangle you only have one jurisdiction. You've got far more people dead."
University of Otago professor and gun safety advocate Kevin Clements said there were 1.5 million guns in New Zealand and no one knew for sure who owned them.
He questioned how most people would feel knowing standard firearms licence holders did not have to register their weapons.
"Most people don't have white supremacist [ideologies] and are not inclined to kill people. But I've been saying again and again you just need one person who contravenes those norms and chaos can follow - and that's exactly what's happened here in Christchurch."
Attorney General David Parker said he supported Ms Ardern's pledge for change but the government was yet committed to banning semi-automatic weapons.
"There's no single answer to the prevention of the atrocity that occurred [on Friday], but certainly, if you had less fearsome weapons it would make a difference."
Brownlee longtime advocate for ban on semi-automatic weapons
Ilam MP Gerry Brownlee told Morning Report he has always supported a ban on military-style semi-automatic weapons.
National MP Hon. Gerry Brownlee on the Foreign Affairs, Defence and Trade select committee.
"I won't be changing from that position. I find it bizarre that people can say they need automatic rifles for sports hunting.
"That doesn't quite fit into my understanding of what you would consider sport to be," Mr Brownlee said.
He said it was necessary to have the appropriate weapons to control predators, such as deer, pigs and goats that damaged New Zealand's natural flora and fauna.
"But I struggle to see how you need to have something that will discharge for a class A licence seven bullets in quick succession and I understand that magazine can be replaced with a 20-shot magazine."
He said he did not want to say too much more because he was not an expert, but he did not understand the need to buy such powerful weapons over the counter.
When asked if it might be possible to have a Parliamentary consensus on banning semi-automatic weapons, Mr Brownlee said he was expressing a personal view but would strongly advocate for it among his National Party colleagues.