Australia's Qantas Airways has grounded its A380 fleet for at least another three days as it investigates oil leaks as a possible cause of the explosion which tore apart one of the superjumbo's engines last week.   

Qantas shares fell as its reputation as one of the world's safest airlines came under the spotlight and investors started counting the financial cost of grounding aircraft and compensating passengers.   

The airline said its six Airbus A380 aircraft would be grounded for at least another 72 hours after an investigation found oil leaks on three Rolls-Royce engines which have been removed from the planes.

Oil leaks in the engines' turbine area were now the focus of the investigation into last Thursday's incident where an engine broke apart above Indonesia's Batam Island, forcing the world's lastest passenger plane to make an emergency landing in Singapore.   

'We are working with Rolls-Royce to ensure we have an appropriate fix to this issue. Our team, Airbus and Rolls-Royce are working around the clock to ensure that. We are not looking at any other alternatives,' chief executive Alan Joyce told reporters.   

Analysts said if the airline's six A380 planes were grounded beyond a week, it could affect the company's profit forecast for this year.

'If they're grounded past two weeks, you'd be a bit concerned,' said Matt Crowe, an analyst at Commonwealth Bank, adding there was unlikely to be a long-term impact on passenger demand due to the incident.

Most of the passengers due to fly on the A380s will be put on other Qantas planes. Qantas has chartered one aircraft from its oneworld air alliance partner British Airways and are talking to other arilines about hiring more.   

Joyce said it had no plans to change its delivery schedule for new A380 planes and it was too early to talk about any legal claim against Rolls-Royce or Airbus.   

Other airlines using the A380 including Singapore Airlines and Lufthansa have been doing additional checks on their aircraft since the incident.   

About 500 Qantas passengers remained stranded in Los Angeles and Qantas said compensation talks would take place after it resolved the issue. Qantas was paying for most passengers stranded in five-star accommodation.   

A second Qantas flight out of Singapore was forced to make an emergency landing after another problem on Friday, this time with the Rolls-Royce engine on a Boeing 747-400 jumbo. - Reuters