Malaysian and Australian investigators examine the piece of aircraft debris found on Pemba Island off the coast of Tanzania. ATSB

The search for missing Malaysia Airlines Flight MH370 will be suspended if the plane is not found in the current search area, Malaysia, China and Australia said in a joint statement on Friday.

The aircraft, with 239 aboard, disappeared in March 2014 during a flight from the Malaysian capital to Beijing. Almost A$180 million ($135 million) has been spent since on an underwater search spanning 120,000 square kilometres (46,332 square miles) in the southern Indian Ocean.

"In the absence of new credible evidence, Malaysia, Australia and China have collectively agreed to suspend the search upon completion of the 120,000-km search," Malaysian transport minister Liow Tiong Lai said.

"I must emphasize that this does mean we are giving up on the search for MH370," he added, in a statement read out to the media.