The disappearance of the aircraft en route from Kuala Lumpur to Beijing in March 2014 with 239 people aboard ranks among the world's greatest aviation mysteries.

Australia, China and Malaysia ended a fruitless A$200-million ($157 million) search of a 120,000 sq. km area in January last year, despite investigators urging the search be extended to a 25,000-square-km area further to the north.

Malaysian Transport Minister Liow Tiong Lai said a Houston-based private firm, Ocean Infinity, would search for MH370 in that 25,000-sq-km priority area on a "no-cure, no-fee" basis, meaning it will only get paid if it finds the plane.

"As we speak, the vessel, Seabed Constructor, is on her way to the search area, taking advantage of favorable weather conditions in the South Indian ocean," Liow told a news conference.

The search will begin on Jan. 17, said Ocean Infinity Chief Executive Oliver Plunkett, who attended the signing event.

Ocean Infinity will be paid $20 million if the plane is found within 5,000 sq km, $30 million if it is found within 10,000 square km and $50 million if it is found within an area of 25,000 square km. Beyond that area, Ocean Infinity will receive $70 million, Liow said.

Its priority is to locate the MH370's wreckage or the flight and cockpit recorders, and present credible evidence to confirm their location within 90 days, Liow added.

"They cannot take forever or drag it on for another six months or a year."

REUTERS