Searchers combing the ocean for missing Malaysian Airlines flight MH370 say vessels have a "one shot" chance to find the missing plane in a specific search area.

Almost one year since the disappearance of MH370, searchers said they were confident they would find the missing plane if it was in the search zone.

The team coordinating the recovery effort released an interview with Paul Kennedy, the project director for the search on behalf of contractor Fugro, who said the team "never go back" to an area once searched.

"Before we go to site we actually have to prove the equipment is fully functioning, so that when we're on location and we start searching, if we run over the aircraft, the debris field, we actually know we will detect it," he said.

"It's a very expensive search, we want to know that if we run over it, we know we don't miss it by accident because we will never go back there again for a second look... it's a one shot deal."

A map shows the MH370 search area off the Western Australian coast. ( Supplied: ATSB )

It will be a year on Sunday since MH370 vanished en route from Kuala Lumpur to Beijing.

There were 239 passengers and crew on board, including six Australians.

More than 26,000 square kilometres of seabed in the southern Indian Ocean has been searched, but so far, no objects warranting "immediate further investigation" have been found.

The Joint Agency Coordination Centre (JACC) and the Australian Transport Safety Bureau (ATSB) have released images that show objects found during the extensive search.

One image showed objects that looked like sea containers, classed as a "category two" find - man-made but unlikely to be significant to the search - with only about 10 of these items revealed by scans.

No objects found on the seabed have been classified as "category one" high interest objects that "warrant immediate further investigation".

No guarantee on search future

Prime Minister Tony Abbott on Thursday told Parliament he could not promise the search for the missing plane would continue with the same intensity.

"But we will continue our very best efforts to resolve this mystery and provide some answers," he said.

He extended his sympathies to the families of the Australians onboard MH370, some of whom were in Parliament, for the "harrowing nightmare" they had endured.

"My pledge is that we are taking every reasonable step to bring your uncertainty to an end," he said.

JACC said the current underwater search area may be largely completed around May this year if there are no significant delays due to vessels, equipment or weather conditions.