The Malaysia Airlines flight disappeared from radar on March 8, 2014 on its way to Beijing from Kuala Lumpur.
Six Australian citizens and one New Zealand resident of Western Australia were on board.
Foreign Affairs Minister Penny Wong has acknowledged the heartache of families of victims. (Joel Carrett/AAP PHOTOS)
Australia's sympathies remained with the families and loved ones, Foreign Affairs Minister Penny Wong said.
"We recognise their ongoing heartache and grief without the answers they seek," she said.
Australia was ready to assist the Malaysian government, Senator Wong said.
"While the searches have not been successful, and families continue to endure such heartache, the effort to find MH370 demonstrates the close co-operation between our countries through difficult times," she said.
"The Australian government is supportive of all practical efforts to find MH370."
Opposition foreign spokesman Simon Birmingham said the anniversary would be difficult for the families of those on board the aircraft.
"For the families, it is a remaining deep personal loss, and one in which trying to solve that mystery would bring some closure, some understanding around that loss," he told Sky News on Friday.
"If there are things that can be done, if there is evidence that shows greater, new searches could make a difference, then of course, that ought to be pursued."
Malaysian Prime Minister Anwar Ibrahim said he was inclined to reopen the investigation if new evidence came to light.
"If we have a compelling case to reopen the investigation, we will," he said on Thursday.
Families gathered in Malaysia on Sunday and called for another search, with the plane believed to have crashed in the southern Indian Ocean.
Searches have failed to find any trace of the missing Malaysia Airlines flight. (Richard Wainwright/AAP PHOTOS)
American company Ocean Infinity has offered to search for the wreckage but the Malaysian government has requested new evidence before it signs off on another operation.
The company's 2018 search came up empty.
The first search was co-ordinated by Australia in 2014 and involved the Malaysian and Chinese governments before it was officially called off in early 2017.
The government was right to ask for more evidence before it searched again and gave false hope to families, maritime security expert Jennifer Parker, who oversaw the operation, said.
Finding a plane at such depths was a needle in a haystack operation and the actual depths of the southern Indian Ocean remained unknown because they were uncharted, she said.
But new technology could help a new search, oceanography expert Chari Pattiaratchi said.
If one piece was found it was likely the whole wreckage would be too and the cold and calm nature of the bottom of the ocean meant parts would still be preserved, he said.
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