Auckland police have been forced to compensate a man for losing track of nine guns he surrendered to them.
In January 2017 the man surrendered eight rifles and a shotgun to the Waitematā station after a Family Court judge issued a temporary protection order against him.
It is standard practice for police to demand a person's firearms and firearms licence when serving protection orders. Police are also required to store the guns until the order is lifted.
In April, when the order was lifted, the man went to the North Shore Police Station to ask for the guns, but they could not be found.
The Independent Police Conduct Authority has found the police failed to tag and store the guns correctly, and arms officers at the station were not aware they'd been handed in.
Police believe the guns were mistakenly destroyed.
But the authority's report said due to "multiple failings to comply with procedure", in particular not completing paperwork, it wasn't possible to determine what happened to the firearms.
CCTV did not capture the transfer of the firearms out of the interim store and a search of district armouries also failed to find them.
The report said there was no conclusive proof that any had been destroyed, because destruction procedures were not complied with, so the possibility that someone with police may have stolen the firearms could not be ruled out.
Two arms office staff told the authority they did not remember seeing the guns at two destructions they attended in early 2017, while a third police officer believed he saw three or possibly four of the guns at a destruction in August 2017.
Destroying the guns would have required a court order or the owner's permission, neither of which police had.
The authority found appropriate procedures were not in place to ensure firearms were properly received, registered, stored and tracked.
It said monthly and six-monthly audits of exhibits were either not conducted or not carried out properly.
Police have apologised to the man and reached a confidential settlement with him.
They now have procedures to account for guns handed in to them.
"Following this incident a full audit was undertaken in mid-2018 and we can say confidently that all other firearms were accounted for and it would appear this was a one-off mistake," Waitematā District Commander Superintendent Naila Hassan said.
Arms Office staff have been spoken to about the accurate keeping of records. They no longer physically handle firearms, a role now done by the Property Exhibits Officer.
The CCTV camera outside the centre's armoury has been moved and now captures a view of its doorway. There is a dedicated armoury exhibit register for all firearms and ammunition.
Ms Hassan said human error was responsible, and the staff involved were still working for police.
"We regret this incident took place, however our staff are only human and errors can occur from time-to-time. I fully support them and the work that they do," he said.