Forty five staff at the base, next to the Preston Bus depot in Deepdale Road, are being transferred to Preston Fire Station in Blackpool Road while a surveyor investigates the site.
A spokesman for the North West Ambulance Service (NWAS), said: “There is severe subsidence at the station and it’s not safe to be in.
“One half of the building is significantly higher than the other and it’s bolted together.
“Everybody is moving to the nearby fire station while a surveyor goes in and decides what is the best course of action. It may be that the building needs pulling down, but we don’t know for sure at this stage.”
NWAS are currently undertaking a review of all its estates as part of cost-cutting measures, and it is unclear what the future holds for a dedicated station in Preston if demolition is required.
The spokesman added: “It’s impossible to say at this stage, but I’d doubt that we would want to get rid of having a station, as it is a main hub in the region.
“We tend to be looking at smaller, more outlying stations at the moment.”
The spokesman also said that NWAS did not own the land the station lies on, and could be asked to move the base elsewhere.
As well as 45 members of staff, with some coming and going as reserves for other stations, there are four emergency ambulances, two rapid response cars, nine patient transport service (PTS) vehicles, one major incident support vehicle and two to three reserve vehicles based at the station.
The building was opened in 1964. Before then, the station was in Argyle Street.