A spokeswoman said the flagship Airbus craft was flying from Singapore to London on Tuesday when oil supplies dropped on one of its four Rolls-Royce Trent 900 engines, but did not pose a safety problem.

"The crew detected a decrease in oil supply to the engine, so they just monitored it throughout the flight," she told AFP.

"The engine was never shut down. There was no need for the flight to be diverted and it landed without any issue."

However, she added that power to the engine was reduced about two hours before landing "as a precautionary measure".

"We always work with Rolls-Royce when things like this happen to engines," the spokeswoman said.

"It has happened previously to another Trent 900 operator other than us. We are obviously in talks with Rolls-Royce to see if this is something that needs a permanent fix."

On Thursday, Qantas estimated that it suffered an Aus$80 million (US$81.1 million) financial hit from November's blast, and said it was still discussing compensation with the British engine-maker.

On November 4, a Trent 900 engine exploded minutes into a flight from Singapore, forcing an emergency landing, in an incident that sent jitters through the industry and prompted Qantas to ground its A380 fleet.