An officer who left loaded gun in a bathroom at Parliament has kept his job and no charges have been laid, following an investigation.
The Diplomatic Protection Service officer left the Glock pistol in the bathroom last June, where it was found by a member of the public.
The inquiry found the officer was on his way to the airport when he realised he didn't have his weapon and asked a colleague to go back and retrieve it.
The colleague arrived a few moments after the pistol was discovered. He secured the firearm, which police said was "intact and unused", an hour and 25 minutes after the officer had discovered its loss.
The inquiry concluded there was no intention to leave the pistol in the bathroom.
However, Assistant Commissioner Mike Rusbatch said the loss should have been dealt with differently once it was discovered "to minimise the risk to the public".
It was "a serious incident" which had been thoroughly investigated and the police realised that potential risk had occurred as a result, he said.
"Our staff are human and we accept that the firearm being left in the bathroom was a genuine mistake', said Assistant Commissioner Rusbatch.
"This incident was without precedent and I am confident that lessons have been learned regarding application of our operational risk assessment model, and our expectations of staff."
Both officers have been dealt with under a confidential police employment process, and remain members of the DPS.
The officer who left the gun behind had been with then-Prime Minister John Key's protetction team for eight years and at the time of the incident Mr Key said it was a catastrophic error, but he still backed the officer.