Firearms have become "ridiculously easy" for offenders to get their hands on and police are being confronted almost daily by gun-wielding criminals, the Police Association says.
The union is calling for an official police inquiry into where the guns are coming from and says the issue has been badly neglected by the top brass.
The call comes days after police were shot at as they pursued a pair of alleged offenders in West Auckland, and follows a spate of incidents where other police were fired on.
There have also been numerous instances in which firearms were aimed at the public, including a Hamilton diary owner who wrestled a gun from a would-be-robber during a dramatic encounter in August, and an armed holdup of a Mangere service station in September in which the offender fired a shot.
"It has become ridiculously easy for... criminals to get firearms. The evidence is apparent as police are stumbling across firearms and becoming involved in armed incidents on a daily basis," said association president Greg O'Connor.
"Contrary to police assurances that armed incidents are 'rare', hardly a week goes by that police are not coming into contact with illegal firearms in the hands of offenders.
"A steady stream of information is coming in from cops on the street. They say there is no doubt that the number of weapons out there is on the increase and gun-toting crimes are becoming the rule rather than the exception... The big question is - where and how are they getting them?"
In the latest edition of association magazine, Police News, Mr O'Connor said firearms in the wrong hands was "an additional risk that police don't need".
Police Commissioner Mike Bush said he was "open to discussion" on the issue, but maintained incidents were "very low".
"While these incidents are of concern, they are actually rare in the context of the thousands of use-of-force incidents police attend annually and given the millions of face-to-face interactions we have with the public."
Mr Bush said police data for 2010-2014 showed gun-related crime had averaged 1.3 per cent of all violent crime recorded, or less than half a per cent of total crime in the past five years.
"While we acknowledge that any firearms incident is a concern, overall, firearms-related offending has remained consistently very low ... Our most recent tactical options reporting data also shows that, in 2014, incidents attended by police where the subject was in possession of a firearm accounted for just 1.5 per cent of all events attended."
But Mr O'Connor said the stats did not show the reality of frontline policing. His staff were compiling their own database of assaults on police and incidents involving firearms based on accounts from members.
In September, 29 staff reported seizing firearms during the course of routine duties, including handguns, sawn-off shotguns, high-calibre rifles, revolvers and pistols.
A significant amount of ammunition was also taken.
Mr O'Connor said police did not officially record what firearms were seized and that needed to change.
"An inquiry needs to be held into whether the prevalence of firearms in what are clearly the wrong hands is a result of any policy, practice or legislative defect in the current environment."
Mr O'Connor said, while in the past the association had called for the arming of police, this issue was not being used as leverage.
"We are asking why it is that offenders, who in the past might have been armed with knives or other weapons, now seem to have ready access to firearms. We believe [what] is urgently needed is an inquiry into why firearms appear to be more readily available.
An inquiry should be done now before one of these incidents escalates into a mass-killing. We need an inquiry to work out what's gone wrong before the disaster happens and more people, including police officers, are shot in a predictable and avoidable incident.
Mr Bush said his top priority was the safety of police staff and the community.
"Any incident... involving firearms or the threat of firearms is of serious concern, given the very high risk it clearly poses to all involved. This is why police are continually working to bring violent crime rates down as a whole, including monitoring and targeting organised crime and drug offending that we know often involves illegal firearms.
"We are also very mindful that our staff work in a dynamic and at times high-risk environment, which is why we continue to closely assess that environment to ensure our staff have the right training and tools to respond to the range of situations they face every day, to keep everyone safe."
Mr Bush said any criminal access to firearms was something police took very seriously.
"Whenever police receive information about illegal, unauthorised or unsafe use of firearms, we actively follow up to ensure this is acted upon and dealt with, either via the courts or through other police action.
"In addition to seizing and destroying illegal firearms, police also encourage unlicensed holders or users of firearms to hand these in to police, who will take their circumstances into account."
Research indicated illicit firearms are far more likely to be obtained by theft. "And this is why the current firearms licensing regime has a very strong focus on firearms security."
Mr Bush said police regularly audited firearms dealers and worked closely with Customs, which was responsible for monitoring gun importation.
"Police remain open to discussion about ways in which the current firearms regime might be strengthened so that criminal access to firearms can be further reduced."
Police did not keep a national register of seized firearms but that could change.
How checkpoint duty can suddenly turn nasty
On August 14, two Hamilton officers were shot at while pursuing a vehicle. They spoke about the incident to Police Association magazine Police News.
The car came to their attention when it appeared to turn down a side road to avoid a checkpoint.
"It quickly became apparent to us that the driver was trying to evade us," Constable Phil Fraser said.
They began to pursue the car and after 3km, it hit and killed a dog. The car was damaged but the driver sped on.
Several kilometres down the road, Mr Fraser and his colleague, Constable Kimmy Muncaster, heard a loud bang. "I said to Kimmy, 'That sounded like a gunshot'... I never fathomed that somebody would shoot at us," he said.
Eventually the offender pulled over, got out of the car and jumped over a bridge into the Waikato River.
He was caught and arrested and the two constables turned their attention to the car.
The rear window was blown out. Inside they found a homemade pistol modified to hold a shotgun cartridge. There was also ammunition, a police scanner and methamphetamine.
A satchel the offender left on the bridge when he jumped contained a Taser, and he revealed he had also discarded another firearm as he fled on foot - a single-barrel sawn-off shotgun with a pistol grip.
"An incident like this really highlights the reality of what we have been hearing is happening on the street," Mr Fraser said.
"We need a change in mindset ... unfortunately things are changing very rapidly."
The Police Association is preparing a database of assaults on police and incidents involving firearms. The information is coming from frontline staff.
In August and September alone, 31 staff sent information about their experiences.
"Members are coming to us with horror stories," association president Greg O'Connor said. "Summed up, it's crims with too much firepower, us with too little."
In September alone, officers found a Mauser .25-calibre handgun hidden in a compartment between the seats of a vehicle; a loaded .22 with a scope in the backseat of a car; a pistol-length pump-action shotgun and a bag of cartridges in the footwell of another.
At one house they found a loaded and actioned shotgun under a couch.