MELBOURNE - As the search for the wreckage of missing Malaysia Airlines flight MH370 nears its end, officials have admitted they might have to confront the idea the plane's disappearance was deliberately planned.

The 12-month search for the plane off the coast of Western Australia, in the southern Indian Ocean, is expected to end in 10 weeks.

The search area, measuring roughly 120,000 square km, was calculated on the assumption that the pilots of the plane were incapacitated at the time it crashed. About 85,000 square km of the seafloor has been searched in that area.

This premise, which has formed the basis of the entire investigation, suggests that the aircraft flew on autopilot until it ran out of fuel somewhere over the Indian Ocean.

If the plane is not found in the search zone, however, it opens the door to the possibility that the plane was being controlled by a "rogue pilot" who crashed it deliberately, killing all 239 people on board.

"We're not at the point yet but sooner or later we will be - and we will have to explain to governments what the alternative is," Martin Dolan, chief commissioner of the Australian Transport Safety Bureau, told The Times of London.

"In a few months' time, if we haven't found it (the plane) then we'll have to be contemplating that one of the much less-likely scenarios ends up being more prominent which is that there were control inputs into that aircraft at the end of its flight."

A part of a plane's wing that washed up on Reunion Island, a French territory in the Indian Ocean, in July confirmed to be from MH370 raised hopes that authorities were close to finding the plane but no further parts have been found since.

Australian, Malaysian and Chinese governments have been launching a massive multinational search for the ill-fated plane.