Malaysia is considering deploying underwater vehicles as authorities prepare for a long-term search effort for missing flight MH370.

Deputy defence minister Abdul Rahim Bakri said national oil company Petronas would provide two autonomous underwater vehicles (AUVs) to help search for the Malaysia Airlines Boeing 777-200, which disappeared without a trace.

"Up to now Petronas has given full commitment, dedicating at least two AUVs to help the search," he said in a press conference.

What is the Bluefin-21? An autonomous underwater vehicle (AUV) designed for deep-sea surveying.

An autonomous underwater vehicle (AUV) designed for deep-sea surveying. It has a "swappable payload". It will first use sonar in the search and will be refitted with cameras if something is detected.

It has a "swappable payload". It will first use sonar in the search and will be refitted with cameras if something is detected. It's 5m long and weighs 750kg. Has an endurance of 25 hours underwater at a speed of 3 knots, with a top speed of 4 knots.

It's 5m long and weighs 750kg. Has an endurance of 25 hours underwater at a speed of 3 knots, with a top speed of 4 knots. It has a depth rating of 4,500m, meaning it will be at its limit in the Indian Ocean search zone.

It has a depth rating of 4,500m, meaning it will be at its limit in the Indian Ocean search zone. Bluefin Robotics says its AUV can also be used for archaeology, oceanography, mine countermeasures, and unexploded ordnance.

As the so-far futile search continues, he said Petronas was also mulling providing underwater sonar equipment and remotely operated vehicles.

Mr Abdul Rahim said Malaysia's oil and gas firm Sapura Kencana was offering a multi-beam echo-sounder which was being considered by the government.

Meanwhile, the underwater search for MH370 is on hold due to communication problems with the Bluefin-21, which was damaged during a mission earlier this week.

Subsequent repairs have revealed issues with transponders on both the probe and the Ocean Shield vessel which is towing it.

Parts have been ordered from the United Kingdom and the Ocean Shield is now heading to Dampier on WA's north-west coast to collect them.

Authorities say the process is expected to take several days, meaning the underwater search will not resume until some time next week.

MH370 vanished on March 8 with 239 people on board, including six Australians, after mysteriously diverting from its Kuala Lumpur-Beijing route.

It is believed to have crashed into the sea far off Australia's west coast.

Air and sea searches over vast stretches of the Indian Ocean have failed to find any wreckage from the plane.

Australia, which is leading the hunt, has stressed that it believes it is looking in the right area based on satellite communications from the plane.

Officials have said an intensified undersea mission will begin once new and more sophisticated equipment to complement Bluefin-21 can be obtained to search at depths of more than 4,500 metres.

The ocean bed in the prospective search zone is not just deep but largely unmapped, meaning specialist sonar equipment and other autonomous vehicles are needed.

Malaysia has vowed to continue the search for the missing plane until it is found.

ABC/AFP