The head of the Police Association says there's no concrete number on how many guns there are in New Zealand.
Association president Chris Cahill told The AM Show he remembers seeing truckloads of guns handed in for destruction in Australia after the Port Arthur massacre.
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Similar scenes could happen here with the Government currently working on gun law reform.
Jacinda Ardern confirmed the Government would change gun laws on Saturday, less than 24 hours after the attack, and confirmed on Monday proposed reform will be announced in the coming weeks.
Cahill expects New Zealanders would be shocked if they were to realise just how many guns are in the country.
"We have no idea how many firearms are in New Zealand.
"We don't register them so we're guessing, we're totally guessing. We know there's up to 50,000 imported every year but we don't know."
He said he's been asking for changes to gun control for years, but now is not the time to celebrate change coming.
"There's no 'I told you so', that's just a sad taste in my mouth, let's just work forward, get it right and do the right thing for these victims and the right thing for the future of New Zealand as well."
Hunting and Fishing has come out in support of reform, and some firearms owners have opted to hand their guns over to police for destruction.
Cahill said seeing organisations support changing the law is a good start, and people will be willing to comply with new legislation when it comes.
"You talk to the majority of firearms holders they'll say they have no issue with registering their firearms and giving the serial numbers, they're more than happy to do that.
"They want to be part of the safety issue."