Officials say the hunt for a missing Malaysian airliner has shifted to a remote part of the Indian Ocean where a British pilot believes the Boeing 777 made a controlled ditching last year with 239 people on board.

The Australian Transport Safety Bureau, which is co-ordinating the search on Malaysia's behalf, said that the patch of ocean south-west of Australia that Captain Simon Hardy has determined is the most likely resting place of Malaysia Airlines Flight MH370 will be searched through December.

Australian authorities, however, said they were not being guided by Mr Hardy's analysis, which has been widely published in recent months.

Martin Dolan, the bureau's chief commissioner, said the search was moving farther south because the southern hemisphere spring makes the extreme conditions in the southern ocean calmer.

"We're aware that we're in the area that Captain Hardy specifies, but we're in that area because it was next in our search sequence, and we've been moving progressively south because the weather is improving," Mr Dolan said.

Mr Hardy used mathematical analysis and a flight simulator to plot the course he believed the airliner took when it vanished during a flight from Kuala Lumpur, Malaysia, to Beijing on March 8, 2014 in one of aviation's most baffling mysteries.

"I am fairly confident that the wreckage will be found within the next four to eight weeks," Mr Hardy told The Australian newspaper.

Experts directing the search have discussed Mr Hardy's theory with him.

"There are many theories from members of the public and various independent experts and all are considered," the bureau said in its statement, which described Mr Hardy's analysis as credible.

But searchers do not accept a key aspect of Mr Hardy's conclusion: that whoever was flying the plane made a controlled landing at sea, which allowed it to sink largely intact.

The only confirmed wreckage of Flight MH370 to be recovered was a wing flap found on a remote Indian Ocean island in July.

Mr Dolan said authorities still believe that the final satellite transmission from one of the jet's engines indicated that it was out of fuel, meaning the plane would have plummeted into the ocean out of control and disintegrated.

Australia and Malaysia have split the cost of the search of the vast expanse of seabed that began in October last year based on satellite analysis of the jet's flight for more than six hours after it went off course. The search, taking place more than 1,800 kilometres off the Australian coast, has so far covered 70,000 square kilometres.

Chinese premier Li Keqiang pledged additional millions over the weekend to fund the continuing search. China lost 153 citizens in the disaster.