A new search for the wreckage of MH370, which disappeared over the southern Indian Ocean in March 2014, is due to start in the middle of January.
It will be carried out by Ocean Infinity, a Texas outfit of sea-search experts using eight underwater drones.
Ocean Infinity signed a contract with the Malaysian government today to receive a bounty payment of up to $A70 million, but only if it is successful within 90 days.
The airliner vanished almost four years ago while flying from Kuala Lumpur to Beijing with 227 passengers and 12 crew on board.
Australia, China and Malaysia ended a fruitless $A200 million search of 120,000sqkm in January last year.
"As we speak, the vessel, Seabed Constructor, is on her way to the search area, taking advantage of favourable weather conditions in the South Indian ocean," Malaysian Transport Minister Liow Tiong Lai said.
Ocean Infinity chief executive Oliver Plunkett, who attended the signing event, said the search would begin on 17 January.
It will be paid $A20 million if the plane is found within 5000sqkm, $A30 million if it is found within 10,000sqkm and $A50 million if it is found within 25,000sqkm.
Beyond that area, Ocean Infinity would receive $70 million, Mr Liow said.
Its priority is to locate the wreckage or the flight and cockpit recorders, and present credible evidence to confirm their location within 90 days, he said.
Ocean Infinity's vessel carries eight autonomous underwater vehicles that will scour the seabed with scanning equipment for information to be sent back for analysis.
It has 65 crew, including two government representatives from the Malaysian navy.
The ship could complete the search within three or four weeks and cover up to 60,000 sqkm in 90 days - four times faster than earlier efforts - Mr Plunkett said.
"It was a unique problem that required a unique solution.
"We looked at it and said, 'let's do something different than what other people would do', and that's the essence of our business."
Ocean Infinity's core business is in the oil and gas industry, as well as sub-sea exploration services for underwater cabling and seabed mapping, he said.
The company's shareholders would bear the upfront costs of the search, Mr Plunkett added.
Debris from MH370 could provide clues to events on board before the crash.
There have been competing theories that the aircraft suffered mechanical failure or was intentionally flown off course.
Investigators believe someone may have deliberately switched off the plane's transponder before diverting it thousands of miles out over the Indian Ocean.
At least three pieces of debris collected from sites on Indian Ocean islands and along Africa's east coast have been confirmed as being from the missing plane.