A Qantas Airbus A380 has been forced to land in Dubai after suffering engine problems en route from Singapore to London.

The incident comes a year to the day since an A380 engine blew up over Singapore.

Qantas says Flight QF31 suffered a problem with oil pressure in its Number Four engine and was forced to shut it down four hours after taking off from Singapore this morning.

The plane flew with three engines for about two and half hours before landing safely in Dubai.

The airline says it is routine for the A380 to fly with three of its four engines and the 258 passengers on board were advised of the problem. All the passengers and crew are safe.

Among the passengers on board was British actor, writer and comedian Stephen Fry, who was returning to the UK after bringing his popular QI quiz show to Australia.

"Bugger. Forced to land in Dubai. An engine has decided not to play," he tweeted.

"We're just stuck on the tarmac: have been for an hour or so.

"I think plan is to bus us to the transit lounge and await International Rescue. This plane, the crew tell me, is going nowhere.

"So either Sydney send another one out or they come to an accommodation with Emirates.

"I should in all conscience add that staff are being wonderful & that morale is high and the passengers understanding and cheerful."

Coincidence

Qantas spokeswoman Olivia Wirth says the airline is working to arrange alternative flights to take the passengers on to London.

Ms Wirth said it was not the same plane involved in last year's incident, describing the timing of today's incident as a "coincidence".

"These things do happen with all airlines around the world, not just Qantas," she said.

"The captain and the flight crew did absolutely everything possible... at no stage was there any safety issue."

Qantas grounded its Airbus fleet on November 4 last year for 19 days after a mid-air engine explosion on a flight bound for Singapore.

The cause of that explosion was found to be a faulty pipe in the Rolls Royce engines.

Union amazed

But the engineers union say it is amazed the airline would immediately distance Friday's incident from last year's near disaster.

Federal secretary of the Australian Licensed Aircraft Engineers Association (ALAEA), Steve Purvinas, told a Senate hearing in Canberra it was too early to determine what caused the latest engine shutdown.

"We've heard preliminary reports that it was related to an oil leak. We don't know if it's an indication problem, a genuine leak ... whether it was a fire hazard," Mr Purvinas said.

"What amazes me is that Qantas can walk out of here today and go do a doorstop press conference and say this is unrelated to the Q32 incident from a year ago.

"They just come out and say these things without inquiries, without investigations and they make assumptions that this was unrelated."