SYDNEY (AFP) - Australia assured family and friends of those on board missing Malaysia Airlines flight MH370 they have not been forgotten, and remained hopeful the plane will be found as it marked the two-year anniversary on Tuesday (March 8) of the aircraft's disappearance.

"I do not think it possible to fully understand how difficult the past two years have been for the friends and families of those on board the aircraft," said Australian Transport Minister Darren Chester on the 2nd anniversary of the disappearance.

"The sense of loss is something they live with on a daily basis.

"A tragedy such as MH370 touches people from all over the world and today we are united in remembering all 239 people who were on the flight."

Mr Chester added that while the search continued, hope remained that the aircraft would be found.

"Finding the aircraft would give answers to the world, in particular the families of missing loved ones, about what happened," he said.

"We have completed around 90,000 sq km of the 120,000-sq-km search zone.

"As we search the remaining 30,000 square kilometre zone in the days and months ahead, Australia, Malaysia and the People's Republic of China remain hopeful the aircraft will be found."

The Malaysia Airlines jet vanished on March 8, 2014 en route from Kuala Lumpur to Beijing with 239 people onboard, mostly Chinese and Malaysians, but also Australians.

It is thought to have crashed after diverting from its course but a huge undersea hunt, at depths of up to 6,000m in the southern Indian Ocean, led by Australia, has so far found no sign of it.

A wing fragment was discovered on an island thousands of kilometres from the search area last July and later confirmed to be from MH370, the first proof that the plane went down.

Two new pieces of debris have been found in the past week, but it is not yet known if they are from MH370.

The three countries have indicated they plan to end the search - projected to cost up to US$130 million - once the designated zone has been scoured unless new evidence turns up.

Families have recently stepped up calls for the hunt to continue and even be expanded if the plane is not found, but search chief Martin Dolan has suggested this appears unlikely, although the final decision rests with the three governments.

"The main piece of missing evidence to solve this mystery is the aircraft itself, which is why we've focused so much effort on the search and on finding it," he told AFP last week.

"And I can't see where alternative information is likely to come from."