Blank firing pistols, traditionally used at the start of a running race, are now falling into the wrong hands, according to the New Zealand Police Association.
The association's president Chris Cahill says it's a growing issue.
"That's the problem we are seeing out on the street now, criminals are buying these. You need no license to buy these, there's no limit to how many you can buy," he says.
Many are legally buying them - then illegally modifying them.
"The problem is criminals have learnt to convert them into real pistols. In other words, firearms that fire projectiles, and it's not what they were intended for," Cahill says.
"We're finding them regularly out there during search warrants or in firearms incidents where criminals are arrested with firearms."
The second Police Amnesty and Gun Buyback scheme is underway, this round targeting semi automatic pistols, pistol carbine conversion kits and AR -15s
Director of Police Amnesty and Buyback scheme Inspector Richard Wilson says lower numbers are expected this time.
"It's a smaller cohort of firearms this time around so we expect there will be much less numbers coming through, the big difference here is there is a change in the legislation that made these firearms newly prohibited."
The Police Association says it's the legislation around starter pistols that now needs to be looked at.
"People that use pistols legitimately for sporting events, they can fire blanks so they don't need these weapons. The groups like athletics and swim clubs don't need them anymore - so why are they in New Zealand? I don't think we need them at all," Cahill says.
The Police Association calling for a change in legislation on starter pistols, because they say criminals already have a head start.