Canterbury police are going to leave their Hereford Street building in Christchurch as a precaution in the event of further damaging earthquakes in Christchurch.
The decision comes on the same day police decided the quake-damaged historic Lyttelton Police station would not be rebuilt.
Assistant Commissioner South Dave Cliff said engineer's advised the Hereford St building has come through the region's earthquakes well, and structural integrity and safety have not been compromised.
Mr Cliff said the building was no less safe than it was before the September 4 earthquake last year, but a precautionary approach was being taken due to the services the building provides.
"The construction of the building is such that in the event of a major earthquake, the building will not fail. However, over time it will begin to show stress and in the event of ongoing significant earthquakes, could reach the situation where doors will not open and close and internal services such as electricity and plumbing may not operate.
"It is for these reasons that we have decided to vacate the building. We have discussed this with Ngai Tahu property, the building owners. This will be managed over the next few months as we locate other accommodation options within the city."
Mr Cliff said engineers have thoroughly inspected the building over the past 15 months and again since last Friday's two big aftershocks, and it remains safe to occupy.
"The aftershocks of 23 December will mean some reassessment of earthquake risk forecasts, with the risk of further significant quakes potentially higher than previously forecast."
While there were already plans to leave the building in the next five years, relocation to a new station will now happen over the next two to three months.
"This decision accelerates those plans. We have already begun discussions with our emergency services partners at Fire and Ambulance over a possible shared facility in Christchurch and these discussions will continue."
Lyttelton Station not to be rebuilt
Meanwhile Lyttelton's quake-damaged historic police station is not to be rebuilt, police have decided.
Inspector Malcolm Johnston, Southern Area Commander, said engineering reports had determined it was uneconomical to repair the station.
He said the news was sad for police, local staff and the Lyttelton community.
"The station is an iconic building for the port town, which has already lost of many of its historic buildings."
The station was built between 1880 and 1882, and opened in 1882, replacing an earlier structure. It is described as being designed in the Victorian Italianate style of the period.
During the February 22 earthquake the building suffered significant structural damage including extensive cracking to the main walls.
"Over the past several months we have worked with our engineers to explore every possible opportunity to repair the station," Inspector Johnston said.
"However we have received advice that to repair the building to an adequate standard would cost at least $1.5 million dollars. That is significantly more than the cost of a new station, and is not economic."
Inspector Johnston said last week's quakes had caused further damage, increasing the cost of repairing the station.
"But we remain committed to Lyttelton and we are giving the local community an assurance that Police will retain a presence here and a new facility will be built."
Police in Lyttelton have been working out of a garage adjacent to the station since February, and a portable building has recently been added to provide further amenities.
Additional temporary facilities are likely to be added to ensure the station can function effectively in the medium-term.
Police may now look at developing a shared facility in the town with other emergency services including the Fire Service and St John Ambulance.