Emergency services are on standby at Sydney Airport awaiting an Air Canada plane which caught fire over Sydney.

Flight AC34 departed Sydney Airport at 10:25 a.m. en route to Vancouver and Toronto and reportedly experienced a fire in the galley which could not be contained.

Fuel was dumped over Hornsby and Longreef.

At 11:53 a.m. the captain reported that he had completed the fuel dump.

It is not known if any dangerous cargo was on board the Boeing 777-233LR.

Ambulances have been alerted to be on standby.

Two years ago, at least 11 passengers and four crew members were injured when the Air Canada Flight 34 from Sydney to Vancouver hit severe turbulence caused by a thunderstorm about one hour northeast of Honolulu.