'Suspicious substance' sparked mail room closure at Hawke's Bay Regional Prison

Police and firefighters were called to an incident at Hawke's Bay Regional Prison. Photo / NZME

A suspicious substance that turned out to be harmless prompted emergency services to race to Hawke's Bay Regional Prison on Monday.

Fire and police were called about 8.30am after the substance was found in a package opened by staff in the mail room at the prison.

"We take threats to the operation of our facilities and safety of our staff extremely seriously and have detailed protocols for dealing with incidents of this nature," a Department of Corrections spokesperson said.

The mail room was closed off, and emergency services were called immediately.

"An ambulance attended the site as a precaution, but staff did not require medical treatment," the spokesperson said.

"Subsequent tests of the material have determined that it was non-toxic and non-hazardous."

There was no disruption to the rest of the prison which continued operating as normal.