The Hall of Justice had to be evacuated shortly after 1 pm on Thursday after smoke was detected in the building.
At around 1.15 pm, judges, lawyers, Judiciary staff and members of the public were alerted by the fire alarm.
There was some confusion as there were no fire marshals were on hand to direct people out of the building or follow an evacuation procedure.
However, the building was evacuated within 15 minutes.
Judiciary spokesperson Carl Francis told Guardian Media maintaince staff discovered that the smoke was coming from a worn belt on an air-condition unit. They repaired the issue and staff were invited to return inside the building.