Brake fault blamed for smoking bus

Passengers have been evacuated from a bus in Perth's CBD after smoke started billowing from the rear of the vehicle.

A brake fault has been blamed for causing the rear wheels to start smoking, with a Public Transport Authority spokesman saying he's confident there was no engine fire on the gas-powered bus.

Passengers were evacuated on Adelaide Terrace just before 9am on Thursday and two fire crews were called to the scene.

Sections of Adelaide Terrace were cordoned off, with one lane closed as fire crews worked to secure the area.

It is believed the bus is the same model blamed for previous gas fires in Perth.

David Hynes, from the PTA, said heat damage and smoke stains were found during a technician's inspection of the bus.