According to a report by The Australian, Qantas confirmed that it had found more problems with its current fleet. As many as six other Boeing 747 aircraft were found to have cracks along with other defects.

"There were some instances of cracks," a Qantas spokeswoman said. "They were immediately repaired and the aircraft have been cleared."

Civil Aviation Safety Authority spokesman Peter Gibson said they would be monitoring investigations closely. The regulator was also waiting to hear back from Boeing, who is conducting urgent investigations into the failure.

"In the first instance (Qantas) did the right thing in inspecting the fleet and that's what we'd expect of a good operator," Gibson said.

"They've identified the problems and rectified them and in the immediate sense that's what what we want to see,” he added.

Earlier this week, a cracked drip tray under the first-class galley leaked onto the main control unit of a B747-400 aircraft as it approached Bangkok. The leak shorted the unit, forcing the plane onto back-up power. Although the jet landed safely, pilots said that the incident would have been disastrous if it had happened further out to sea.

Another Qantas passenger travelling on QF10 from London to Melbourne told The Australian that the plane came to a complete stop before reaching the runway in Singapore with no power, lights or engines.