A fire in Ōtāhuhu Police Station's server room has resulted in extensive water damage.
The fire started just before 1am on Thursday morning.
Police said overnight staff were able to evacuate the building safely and the fire did not spread to other parts of the building.
But they said the sprinklers caused extensive water damage throughout the building.
A spokesperson said office staff cannot use the building but front-line officers are unaffected.
Staff have been moved to the nearby Māngere Police Station.