The front counter area at the Greymouth Police Station has been closed temporarily to the public due to mould.
"The station has been experiencing some issues with mould due to water ingress," a police spokesperson said.
Police ask locals to call 105 to report non-urgent matters during the closure.
It comes after air quality testing in the building revealed "higher than acceptable limits" in the front counter area and other parts of the station.
The spokesperson said the front counter could be closed for weeks until air quality tests improve.
"Local police will maintain a 24/7 response capability and will respond to jobs as normal," they added.
Affected staff will relocate to alternative sites temporarily.
A mobile police base is likely on its way to Māwhera Greymouth, "to provide a way for our community to meet with us face-to-face".
The public can report non-urgent matters by calling 105, or by going online - alternatively in an emergency call 111.
