Sydney - A Qantas flight bound for Manila on Saturday returned to Sydney and made an emergency landing.

An Air Services Australia spokesman said the pilot declared an emergency, dumped fuel and turned back shortly after take off.

"Air traffic controllers received a call from the pilot declaring an emergency and proceeded to give priority clearance for a landing at Sydney," the spokesman told Australia's AAP news agency.

The cause of the emergency is as yet unknown.

A Qantas jet was forced to make an emergency landing in Manila a week ago after an exploding oxygen cylinder in the cargo bay ripped a hole in the fuselage and shards of metal pierced the cabin.

The plane was flying to Melbourne from Hong Kong. The incident prompted Qantas to inspect the oxygen cylinders on all its 747 aircraft.

On Tuesday a mechanical fault forced a Melbourne-bound Boeing 737 to return to Adelaide. A wheel-bay door failed to retract fully on Flight 692 and the pilot followed standard procedure in returning to Adelaide.

Since its establishment in 1920, Australia's national carrier has yet to lose a jet to an accident. (dpa)