Specialist police officers have used a bomb disposal robot to investigate a security alert at Brisbane’s courts complex.

The area surrounding the neighbouring supreme and magistrates courts in the city’s CBD was sealed off on Thursday.

The robot was used to examine a car on Roma St, a measure police say was precautionary.

They later declared the area safe.

Detectives are questioning a man in connection with the incident.

A police spokeswoman told AAP initial reports were of a man acting suspiciously.

The police service later tweeted: “Specialist police are now outside the courts complex to conduct investigations as a precautionary measure.”

Both roads were reopened to traffic and pedestrians after the car was examined.

Reports of a man dropping a mobile phone under a Queensland government car parked outside court sparked the lockdown, Inspector Darren Smith said.

The man was reportedly seen loitering and acting suspiciously and is still being questioned, Insp Smith said.

But a preliminary investigation found no untoward conduct.

He said the bomb squad had been called as part of an “ordinary” response by police after the 10.20am call on Thursday.

“The vehicle is a Queensland government vehicle and any activity where you find someone acting suspiciously, or a report of (them) acting suspiciously in a public place, will always be taken seriously.”