SYDNEY Tests have uncovered oil leaks in three Rolls-Royce engines on Qantas' grounded Airbus A380s, the airline's CEO said today, as engineers tried to zero in on the cause of an engine failure on board one of its planes last week.

Australia's national carrier grounded its six double-decker A380s, the world's newest and largest airliner, after an engine burst minutes into a flight from Singapore to Sydney last week, scattering debris over Indonesia's Batam island. The plane made a safe emergency landing in Singapore.

Engineers conducted eight hours of extensive checks on each engine over the weekend.

Toay, CEO Alan Joyce said engineers have discovered oil leaks in the turbine area of three engines on three different A380s.

Because of that, he said, all of the airline's A380s will be grounded for an additional 72 hours.

Lufthansa and Singapore Airlines, the other airlines that fly A380s fitted with Rolls-Royce's Trent 900 engines, also briefly grounded their planes last week but resumed services after completing checks.