PM Jacinda Ardern demands 'please explain' over Palmerston North police station gun burglary

The Prime Minister has demanded a 'please explain' from the country's top cop over how a man was able to break into a police station and walk out with 11 guns.

The burglary has raised questions about the police's ability to handle the gun amnesty scheme.

The Palmerston North police station was robbed of 11 firearms because of a serious case of human error: staff accidentally left a roller door open.

The alleged burglar got through two more doors and was then able to walk straight back out with the firearms, one of which was a banned weapon under the new gun laws.

Deputy Police Commissioner Mike Clement told The AM Show it was "unacceptable by any standard, especially our own".

Police have been charged with collecting, storing and destroying tens of thousands of firearms as the gun amnesty gets underway.

The Prime Minister said she was aghast at the burglary, and ordered Police Minister Stuart Nash to get some answers.

"The Commissioner is undertaking the work to give reassurance to the public that the buyback scheme will be safely executed," Jacinda Ardern told media.

She said the roller door mistake was "completely against not only policy protocol but good common sense".

Since March 15, nearly 400 firearms have been turned into police, and more than 2000 gun owners have gone online to tell police they have firearms they want to hand in.

Police are preparing for an influx of thousands of guns. They still have no idea how many, but Newshub understands they don't have the capacity to store even those they do have records for - about 13,000.

"Our preference is not to have those firearms handed in to police stations," Clement said. "While we do have armouries in the stations, they aren't equipped to deal with tens of thousands of firearms."

Police are still working out just how they'll handle so many guns, and are expected to announce details by the end of May.

Newshub understands their first job is to meticulously plan how the buyback will work, including designing a completely new software system which will essentially be a track and trace like that used for courier parcels. It will track every gun, part and magazine from collection point to destruction point.

Collection points are still being worked on too. Police stations might not be the best place for this in every case, and the Government is looking for other options such as the 171 gun clubs around the country. The understanding at this point is that guns will be stored and destroyed by the New Zealand Defence Force, but there's still the question of short-term storage before bulk transportation.

When it comes to that lack of storage capacity, Newshub understands they're looking at temporary storage options which could include using shipping containers.