MPs considering a review of gun laws have been told it's very likely there will be another mass killing in New Zealand, like the one that happened at Aramoana in 1990.

The owner of New Zealand's largest gun retailer doesn't agree that another mass shooting is "inevitable" unless the country's gun laws are tightened.

Gun City owner Dave Tippell ridiculed the suggestion and said there simply wasn't a problem to fix.

The claim was made in a select committee hearing at Parliament on Wednesday, where a law professor and police union boss both urged MPs to create a register for firearms.

SUPPLIED/NZ Police In March this year, police seized an average of four firearms a day, including this haul from the ceiling of a house in Takanini, Auckland.

In March, Parliament's law and order select committee launched an inquiry into the illegal possession of firearms following a number of high-profile incidents, including the discovery during a police raid of 14 military assault-grade AK47s and M16s.

Waikato University law professor Al Gillespie told MPs that the risk of a mass shooting in New Zealand was growing due to the threat from right-wing and religious terrorists, along with "lone wolf" attacks as seen in Europe and the United States.

READ MORE:

* Trade Me grilled on gun sales

* Parliament to hold inquiry on NZ gun laws

* Kawerau siege: Is it time to look at our gun laws?

* Illegal gun possession not a new problem: lawyer

* AK47s in south Auckland bust

* No records of stolen guns

* 'Culture change' in the black market for unlicensed guns

NZ POLICE Parliament decided to launch an inquiry into illegal firearms after a number of cases where police found caches of military-type guns, including those pictured at a South Auckland house.

"It is, to me, completely foreseeable that there will be another Aramoana in this country."

Tipple, owner of Gun City - the largest New Zealand gun retailer, disagreed.

"We've got the best record in the world of firearms ownership and the lowest rate of illegal use."

SUPPLIED/UNIVERSITY OF WAIKATO University of Waikato law professor, Al Gillespie, says it is "completely foreseeable" that New Zealand will experience "another Aramoana".

"We do not have a problem."

Tipple said military-style semi automatic weapons made up less than one per cent of Gun City sales in a week, or about 10 guns.

He said the attraction for the guns were that they were "technically excellent" and "reliable" and were mainly used for hunting, target shooting and in competitions.

KEVIN STENT/FAIRFAX NZ Police Association president Greg O'Connor says a gun register is the best way to stop firearms from falling into the wrong hands.

However Gillespie told MPs stockpile and strength of firearms in the country was growing, while the "dark web" had made it possible for people to illegally buy firearms parts and put them together at home.

"They're practically impossible to detect at Customs, because the Customs officer doesn't know what this spring is for."

Gillespie said the Government should tighten storage requirements and the rules for gun safes, so they could not be easily broken into.

While a prohibition on certain types of guns was an option, Parliament could also look at a ban on large-capacity ammunition magazines, as well as certain bullets such as the .50 calibre.

"They have the capacity to go through pretty much anything, including a police vest."

'WE CAN'T STOP GUN CRIME, BUT WE CAN DO OUR BEST'

Gillespie also backed a gun register, particularly for higher-power weapons and those which could be made more dangerous.

Firearms already had a unique identifier when they came into the country, and when they went from Customs to wholesalers, so little effort was needed to create a register.

Other possible changes included an amnesty and buyback regime for people with unlicensed firearms, as well as stronger sentences for illegal possession of firearms.

It was important to deal with the issue before a mass shooting happened and the public demanded stronger restrictions like a complete ban.

"We can't stop gun crime, we can't stop criminals doing bad things, but we can do our best to minimise the risk."

MASS SHOOTING 'INEVITABLE'

Police Association president Greg O'Connor also believed a mass shooting was "inevitable", telling MPs police had noticed a massive increase in the number of firearms among "those who simply should not have them".

"We've already had mass killings, there are mass killings happening in the United States, we would be naive to think we're not going to have one here."

O'Connor accepted there was "no political will" for the police to be routinely armed, but said action was needed to reduce the risk police faced from firearms.

It was too easy to illegally obtain firearms, and a register was the best way to ensure people could be held to account if a gun went into the wrong hands.

O'Connor expressed concerns about under-reporting of firearms seizures by police, saying the official police database lacked cases reported on an unofficial register run by the association.

It was likely police were underestimating the scale of the problem due to their record-keeping, he said.

"The whole emphasis on firearms policing has been low...firearms has been the poor relation for police for some time."

'DISCREPANCIES' IN GUN SEIZURE NUMBERS

Labour police spokesman Stuart Nash said he was "astounded" by police problems in cataloguing gun seizures.

"In the 21st century, in this day in age, you would think just one entry of a seized weapon would seem to suffice."

A police spokeswoman acknowledged there could be "some under-reporting of firearms seizures", saying a number of systems were used to record information which could cause "discrepancies".

"To address this, police is currently working to streamline the system for recording such seizures, and reminding staff of the correct process to follow."