Kuala Lumpur, Mar 8 (IANS): The crew searching for the Malaysia Airlines flight MH370 on Thursday said that they "remain optimistic" of finding the missing plane.

Two Malaysian navy officers aboard the search ship, Azmi Rosedee and Adbul Halim Ahmad Nordin, told the New Straits Times they were "doing their utmost", even as the search was slowed by bad weather and tricky underwater terrain in the Indian Ocean, reports the Guardian.

The renewed search for the MH370 began in January after the US-based company Ocean Infinity was hired by the Malaysian government.

A previous three-year search coordinated by Australia was called off in 2017 after it failed to find the plane.

After 43 days of searching, Ocean Infinity's ship, Seabed Constructor, is yet to find anything.

"We have gone through a number of rough days," Rosedee and Nordin said.

"Operations continue even when the sea is rough … but it makes it difficult for us to deploy and recover the AUVs (search vehicles). This slows us down.

"Aside from that, the seabed of the search areas is hilly and uneven. This also disrupts the AUV's capability to thoroughly sweep the areas."

In February, the Australian Broadcasting Corporation revealed that the presence of Malaysian military on board Seabed Constructor had sparked a "power struggle", with concerns the Malaysian government wanted stricter oversight and military control over the search, the Guardian reported..

On Thursday the Malaysian navy chief, Admiral Tan Sri Ahmad Kamarulzaman Ahmad Badaruddin, defended the presence of the naval officers, Rosedee and Nordin.

"Since the cost of this search will be borne by the government, it is necessary to have our representatives on board to observe the operation," he said.

The MH370 disappeared four years ago on March 8, 2014, en route from Kuala Lumpur to Beijing, with 239 people on board, sparking the largest search in aviation history.