The official search for MH370 in the Indian Ocean has been reduced to one ship, Australian authorities said Wednesday, as relatives of the missing passengers launch their own hunt for crash debris in Madagascar.

The Fugro Equator, one of four vessels involved in the search, remains in the 120,000 square-kilometre (46,000-square-mile) zone where investigators believe the Malaysian Airlines jet went down.

The ships, three of which were contracted from Dutch firm Fugro, had been scouring the southern Indian Ocean off Western Australia state for the Boeing 777.

China's Dong Hai Jiu 101, which was hunting for debris with a remotely operated vehicle -- a device tethered to a ship by a cable -- departed on Saturday, the Australian Transport Safety Bureau (ATSB), said.

The plane disappeared en route from Kuala Lumpur to Beijing on March 8, 2014 carrying 239 passengers and crew.

No trace of the jet has been found, but investigators have confirmed that three pieces of debris recovered along western Indian Ocean shorelines came from MH370.

With more than 110,000 square kilometres already examined, the Fugro Equator's mission was expected to wrap up by February next year, the ATSB said in a statement.

The news came after families from Malaysia, China and France gathered in Madagascar's capital Antananarivo on Monday as frustration grew over the failure to find the aircraft.

The relatives were set to distribute brochures educating villagers on how to identify plane debris.

Many next-of-kin have repeatedly complained about the lack of a coordinated search in the western Indian Ocean and along the African coast.

The ATSB said in a report last month that MH370 was likely out of control when it plunged into the ocean with its wing flaps not prepared for landing. It cast doubt on theories a pilot was still in charge.

The governments of Australia, Malaysia and China, where most of the passengers were from, agreed to pull the plug on the operation once the search area was fully scoured unless "credible new information" emerged.

grk/amj/eb

FUGRO

Malaysia Airlines