A multi-storey Adelaide police station will be closed for "several weeks" to determine the cause of cracks. after staff were forced to evacuate.

Key points: Cracks have formed at one end of Sturt Police Station

Cracks have formed at one end of Sturt Police Station Police heard a rumble and the building was evacuated

Police heard a rumble and the building was evacuated Staff have been forced to operate from the carpark

Officers at the Sturt Police Station in Adelaide's south last night noticed "what appeared to be structural movement" at the western end of the building after hearing a rumble.

Police said no-one was injured, and no members of the public or any prisoners were at the station when the incident occurred.

Earlier, they described the evacuation as a "precaution" and said police patrols were currently operating out of neighbouring stations.

"It's a bit of a concern. 'Round about 7:00pm patrols were inside the station when they heard a rumble," Senior Constable Mick Abbott told ABC Radio Adelaide.

"The police station is going to be inspected this morning and then hopefully normal operations can resume, but at the moment the station is closed.

"Obviously [they'll] get engineers or someone to have a look at it and hopefully it's not too bad, but we'll have a bit more information later on today."

A car crashed through the building in 2016.

There had been speculation on social media the cracking and rumble might have been the result of an earthquake, partly because of previous seismic activity in the area.

However, authorities have suggested that was not the case.

"Geoscience Australia has not detected any earthquakes in the region at that time," a spokesperson for the agency said.

Staff remaining at the site — at Sturt Road between South and Marion roads — were forced to operate front counter services from a vehicle in the carpark.

"Members of the public who do not have urgent business or who are able to are asked to attend another station," police said.

This afternoon, police confirmed the station would be closed for until further notice to ensure the safety of staff and the public.

Police Commissioner Grant Stevens visited the site today and spoke to engineers and staff.

The decision was made to keep the building closed while the situation was assessed.

Police admitted the process could take several weeks.

Services will be extended at the nearby Netley Police Station, with opening hours extended to 9:00am to 9:00pm, seven days a week.

Access to the station has been restricted following the incident. ( ABC News: Claire Campbell )

A spokesperson from the Department of Planning, Transport and Infrastructure (DPTI) said road upgrades in the area had not impacted the station.

"The issues experienced last night at the Sturt police station are not related to the Gateway South project," the statement said.

"Vibration monitoring equipment installed for the Flinders Link Project have not detected any movement.

"Please note the site has been susceptible to minor movement historically, and DPTI is involved in required assessments or minor rectification works."

The station is not far from the Darlington road project, where rain damaged concrete installed as part of a $620 million upgrade, causing it to crack and slide.

In May 2016, a car crashed into the front of the station, smashing two automated glass doors during the early morning.

Darlington was the epicentre of Adelaide's 1954 earthquake which measured 5.5 on the Richter scale and was widely felt across Adelaide.

After the quake, some buildings in the southern suburbs were demolished due to cracking.