A state public transport bus has exploded into flames on an arterial road on the edge of Sydney's CBD causing "extreme" smoke and 2-metre-high flames.
"At approximately 7:30pm, a gas bus operating route 394 from La Perouse to the City caught fire," a NSW Transport spokeswoman said.
Surry Hills resident Phil Dye was working with headphones on when he heard a loud noise and saw smoke in the sky. He went to his balcony, which overlooks Flinders Street and South Dowling Road intersection, to investigate.
"There was smoke pouring out of the bus — all of the doors were open," Mr Dye said.
"As I was watching and starting to take a photo, the bus sort of exploded more at the back and the flames started to leap out."
Mr Dye said he could see clearly into the bus and he could only see a driver on board with no passengers.
"The driver got out pretty quick and the driver was telling people to stay away, obviously in case it exploded even more," he said.
The loud noise to the final explosion happened in less than 30 seconds, Mr Dye said, with the first fire engine arriving about four minutes after the explosion.
"No-one was going near the thing, I can tell you, the smoke was extreme and the flames were probably about 2 metres high from the back of the bus."
The fire was extinguished with white foam.
Flinders Street, which extends south into Anzac Parade, has been reopened to traffic.
No-one was injured in the fire.
A spokeswoman from the office of NSW Transport Minister Andrew Constance said that private and state transit buses had been fitted with a fire suppression system by August this year, and all new buses had the technology.
"Over the last two years we have retrofitted 2,335 private operator buses and 1,300 State Transit buses," she said.
The Office of Transport and Safety Investigations would investigate the bus explosion and inspect the bus tomorrow.
