A bus carrying passengers across the Sydney Harbour Bridge caught fire on Thursday afternoon (September 15) causing major traffic delays during peak hour.

Australian media reported that several lanes on the bridge had to be closed while the fire was extinguished and the bus towed away.

About 30 passengers were evacuated off the bus, with three treated for smoke inhalation, local media said.

Some city-bound and northbound lanes were later reopened.

Investigators are still to determine the cause of the fire.