A Chinese ship mapping the ocean floor ahead of an intensive underwater search for missing Flight MH370 was returning to port Saturday due to a technical problem, officials said.

The massive Indian Ocean search for the Malaysia Airlines plane, which disappeared on March 8 carrying 239 people, has so far failed to find any sign of the Boeing 777.

The Chinese survey ship, Zhu Kezhen, was conducting a bathymetric survey -- or mapping of the ocean floor -- to help experts determine how to carry out the next stage of the search on the previously unmapped ocean seabed.

"Zhu Kezhen suffered a defect to its multibeam echosounder and is coming into port to conduct the necessary repairs," Australia's Joint Agency Coordination Centre said in a statement.

"The journey is expected to take a couple of days."

The search for MH370 has been continually frustrated and last week Australia ruled out an area considered a possible resting place of the plane after a mini-sub dived repeatedly to the seabed and found nothing.

Officials believe the plane diverted from its Kuala Lumpur to Beijing route and ended up in the vast Indian Ocean, but have little to go on besides satellite signalling messages sent between aircraft, satellite and ground station.

Experts are now reanalysing this satellite data to confirm a search area as well as mapping the sea floor in preparation for the commercially contracted deep sea search, which is expected to begin in August and take up to 12 months.

JACC said an Australian contracted survey vessel will also be involved in conducting the bathymetric survey, and will arrive in the search area in June.

Australia is leading the hunt for MH370 which disappeared in its search and rescue area, in consultation with Malaysia and China, whose citizens accounted for nearly two-thirds of those onboard the Beijing-bound flight.

Malaysia insists it is doing all it can in what is an unprecedented situation but the relatives of those on the plane have expressed anger and frustration at the lack of progress, nearly three months after the plane vanished.

Malaysian Prime Minister Najib Razak, speaking in Beijing on Saturday during a state visit to China, said the disappearance of flight MH370 had "tested" the friendship between the two countries and pledged to find the missing plane.

"Facing a mystery without precedent, we were grateful for the support of the Chinese government, which has spared no expense in the search effort," Najib said in a speech commemorating the 40th anniversary of the establishment of diplomatic ties between the two countries.

"We will not rest until the plane is found," he said, according to a speech transcript.