KUALA LUMPUR, Malaysia -- The search area for the missing Malaysia Airlines Flight 370 will be expanded by another 60,000 square kilometres in the Indian Ocean if the jetliner is not found by May, officials said Thursday, affirming their commitment to not give up until it is located.

Malaysian Transport Minister Liow Tiong Lai said that Malaysia, Australia and China, which are leading the hunt for the Boeing 777 that went missing on March 8 last year, are "committed to the search."

He told reporters after meeting with his counterparts from the other two countries that so far 61 per cent of the 60,000 kilometre search area has been scoured off Australia's west coast. The remaining 39 per cent would have been searched by the end of May, he said.

"If the aircraft is not found within the 60,000 square kilometres, we have collectively decided to extend the search to another 60,000 square kilometres within the highest probability area," he said. However, searchers are hopeful that they can find the plane in the current search area, he said.

The announcement removes some ambiguity about the future of the search as it was never made clear what would happen if the plane is not found. It will also come as a solace to the relatives of the victims, who are holding out the hope of recovering the bodies.

Liow said the two areas together would cover 95 per cent of the Indian Ocean flight path of the plane, which went missing while flying from Kuala Lumpur to Beijing with 239 people on board. Most of the passengers were Chinese. It dropped off radars, and investigators using satellite data later figured out that it made a series of turns and flew in a direction opposite from its original heading before crashing into the Indian Ocean.

"We are confident we are searching in the right area," Australian Deputy Prime Minister and transport minister Warren Truss said at the news conference, alongside Liow. "We are confident we have the best search equipment ... if the plane is in the area we will find it."

In the first phase, a total of 120 million Australian dollars ($93.6 million) was spent by the Australia and Malaysia, split equally, and Liow said the next phase is estimated to cost A$50 million ($39 million). The costs are lower in part because the vessels and equipment are already in place.

"Australia and Malaysia have been sharing the cost and we will continue to do that," Truss said. "We are confident we will be able to fund whatever is necessary."

The lower cost is because the equipment has already been purchased.

The two ministers said they expect the second phase to take the rest of this year, but a subsequent statement said it could take up to a year. Bad weather during the southern hemisphere's upcoming winter and rough, rugged terrain under the remote seas are expected to hinder the search and cause delays.

The statement issued after the meeting said the ministers also agreed on plans for recovery activities, including securing evidence, in the event the aircraft is found, but gave no details.

In late January this year, Malaysia's government formally declared the plane's disappearance an accident and said all those on board were presumed dead. A comprehensive report into the disappearance found no significant anomalies in the flight, except that the battery of the locator beacon for the plane's data recorder had expired more than a year before the jet vanished.

That still does not explain what caused the plane to veer so off course in what has become aviation's biggest mystery that continues to confound experts and investigators alike. At the same time, the relatives of the dead have had no closure and many still believe that their loved ones may be alive amid a host of conspiracy theories including one that the plane was hijacked and landed somewhere safely.

One theory also has the plane flying west to Maldives. Truss said the plane may have had enough fuel to reach Maldives but it would have been impossible for it to be in the reported area in daylight and not be seen by anyone. Also, the flight path to Maldives would be inconsistent with satellite and radar data. "It is not considered a likely possibility," he said.

China's transport minister Yang Chuantang said China may contribute vessels and other assets in the next search phase.

"We will marshal some physical assets including vessels to participate in the search," he said. "We will not waver in our commitment to continue the search until we find the plane and resolve the mystery."