Northland police have encountered 505 firearms in just over a year, more than any other district except Canterbury.
The firearms were found during 145 separate incidents across the region between October 1, 2020, and November 30, 2021.
The incidents were recorded as part of the Gun Safe programme, where police now register all incidents believed to involve firearms.
A police spokesperson said the high number of guns per event was largely due to search warrants, such as those executed as part of the nationwide Operation Tauwhiro.
"This can be attributed to a number of search warrants, either through investigations, operations, or as part of our routine policing."
Between February 2021, when Operation Tauwhiro was launched, and March 1, 2022, 1531 firearms had been seized and 1255 arrests made.
Operation Tauwhiro specifically targeted gun-related violence by gangs, aiming to disrupt their supply of firearms.
"Police has been very open recently around some of the behaviours from organised crime groups using firearms against one another and we also note significant arrests have been made in relation to these gang tensions," the police spokesperson said.
Data from the previous 19 months, from March 2019 to September 2020, showed Northland police had the lowest number of firearms incidents and came across the fewest firearms of any district in the country, at 256.
Despite the high number of guns found over the next 13 months to November 2021, the number of events involving firearms In Northland was the second-lowest, after Tasman district.
Police said the issue of an increasing number of firearms encountered was national, rather than Northland-specific.
"While the data does indicate a gradual trend upwards, the issue of firearms within our communities is not just confined to a single region."
Police Association president Chris Cahill also said police were seeing guns more frequently on the job than they used to.
"They're just coming across them more and more often in situations like in routine vehicle stops, routine search warrants."
Most guns seen in these incidents were either stolen from legitimate firearms owners or were obtained by unscrupulous firearms licence holders on behalf of others, Cahill said.
"Because we haven't had a gun register for so long we really don't know where our firearms are, who has them and what they're doing with them."
It was important to get a gun register up and running, he added, to keep track of all firearms and limit the number that fall into the wrong hands.
Licensed firearms owners needed to make sure their weapons were secure, Cahill said, not leave them in vehicles and store bolts separately if possible.
"It is tempting to leave them readily available but of course, that opens them up to theft so we ask them to make sure they're secured safely."
Federated Farmers Northland president Colin Hannah also said it was important to keep firearms stored in a locked cabinet.
However, he said he knew of one incident where a house was deliberately targeted by thieves who broke into a "very, very secure" gun case and stole firearms.
"There's huge demand for it on the black market," he added.
Hannah said while he expected some of Federated Farmers' younger members may have an issue with it, he was in favour of a gun register.
"Personally I think that's probably the way to go, I wouldn't have any problems myself with that ... I think the majority of our older farmers would be used to that."
A law passed in 2020 provided for the creation of a firearms register, but gave people five years to register guns.
Firearms licensing was also changed and penalties were increased for firearms offences as part of a second change to gun laws following the Christchurch mosques terror attack.
This followed a ban on certain firearms, including most semi-automatic weapons and large magazines.
Cahill said a "significant number" of frontline police wanted to be routinely armed due to the recent increase in encounters with firearms.
"It's not really that they want to be, it's that they feel there's a need given how often they come across firearms."
The Gun Safe data for Northland recorded more rifles than any other type of gun, comprising 362 of the 505 firearms from 2020 to 2021, and 80 of the 256 from March 2019 to September 2020.
Nearly half of the 505 firearms in the more recent data, 250, were surrendered and 197 were seized.
None of the firearms found from 2019 to 2020 were recorded as surrendered and 221 were seized.
There were just 17 prohibited weapons recorded over two and a half years, all of which were seized by police.
Just one firearms incident involving at least one death was recorded in Northland from March 2019 to November 2021, and there were seven involving injuries.
Nationally, police have encountered more than 10,000 guns in three years. Northland police have come across 761 firearms since Gun Safe was launched in March 2019.