New Zealand is in danger of another mass shooting, like the 1990 Aramoana massacre that left fourteen dead and the country stunned, according to an expert on illegal firearms.

Warnings of mass-shootings have been raised at a parliamentary inquiry about illegal guns following a spate of attacks on police, like the incident in Kawerau in March this year when four officers were wounded.

Waikato University professor Alexander Gillespie told the inquiry that 95 per cent of guns in new Zealand are untraceable.

"At the moment I have to register my car. I have to register my dog. But my neighbour doesn't have to register his firearm," says Dr Gillespie.

"There is great risk of terrorism and there is a great risk of lone wolf attacks," he says.

There's also an online market where people can buy guns in separate pieces.

"The problem is when it is sent over in bits Customs can't often identify the parts as a complete firearm," says Dr Gillespie.

ONE News has discovered that guns are recorded when they come into the country, when they go to a gun dealer, but there's no central register of where they're sold after that.

Also, police aren't keeping accurate records of every illegally seized weapon, says New Zealand Police Association president Greg O'Connor.

"Yes, there is a considerably higher number of firearms that were seized than were ever reported to the public," Mr O'connor told ONE News.

But gun shop owner David Tipple says its people who are the problems, not guns.