A man who was being questioned by police in relation to a bomb scare in Brisbane's CBD has been released without charge.

Police have reopened streets near Brisbane's court precinct after this morning's security scare.

The police bomb squad was called in just after 11:00am (AEST) after a man had been spotted acting suspiciously near a car parked close to the Supreme Court.

The sedan belonged to a senior Gold Coast detective and was parked in a loading zone outside the Roma Street court complex.

It is understood the man dropped a mobile phone under the detective's car.

Police cordoned off the area so the bomb squad could check under all the cars in the loading zone with a robotic device.

Police say the bomb squad was unable to find anything suspicious.