Rolls-Royce is to temporarily replace complete jet engines suffering from oil leaks which came to light after one disintegrated in flight, aviation sources said today.

The engine-maker will remove faulty engines and replace them with new ones. It will then fix the leaking part and swap the engine back again.

On November 4 leaking oil in one of a Qantas A380's four massive Trent 900 engines caught fire, heating metal parts and wrecking it over Indonesia forcing the airliner to return to Singapore.

Experts said flying metal damaged vital systems in the wing of the Sydney-bound plane, causing the pilots to lose control of the second engine and half of the brake flaps on the damaged wing in a situation far more serious than originally portrayed by the airline.

Qantas grounded its six A380s within hours and said four days later that checks had revealed suspicious oil leaks in three engines on three different grounded A380s.

Singapore Airlines and Lufthansa, which both use A380s with Trent 900 engines, have conducted checks on their superjumbos and all but one have returned to service, the airlines say.

Qantas' six superjumbos - the backbone of its longest and most lucrative international routes between Australia and Los Angeles, Singapore and London - remain grounded despite what experts say is financial pressure to fly them again. The removal of engines can be expected to cause longer delays and potential revenue losses.

"We are taking our normal and extremely conservative approach to safety and will not operate our A380 fleet until we are completely confident that it is safe to do so," a Qantas spokesman said.

Airbus said last week that the Trent 900 problems could be expected to delay deliveries of new A380s.

Rolls-Royce, the world's second-largest engine maker, said on Friday that it would be replacing an unspecified module, or collection of linked parts, on the Trent 900.

Airbus said Rolls-Royce would also be equipping the engines with software to shut them down before an oil leak could cause an engine to disintegrate.

Singapore Airlines, which grounded three of its 11 A380s after checks found oil leaks in three Trent 900s, said today that two were back in service after engine changes and that work was continuing on the third.