Transport ministers from Australia, China and Malaysia will meet Friday to discuss the future of the frustrating deep-sea search for missing flight MH370, officials said Wednesday.

The Australian-led search is scouring the seafloor within a designated 120,000-square-kilometre (46,000-square-mile) belt of remote Indian Ocean where authorities believe the Malaysia Airlines passenger jet may have gone down.

Searching is expected to be completed possibly in the next few weeks, and the three countries have said the hugely expensive high-tech sonar operation far off western Australia will not be further expanded without "credible" new evidence pointing to a crash site.

"The search has been unprecedented in both size and scale, conducted in some of the world's most isolated waters and at times in extremely challenging weather," Australia's Transport Minister Darren Chester said Wednesday.

"The meeting will provide an opportunity to reflect on achievements to date and discuss next steps as we near completion of the 120,000 square kilometre search area," he added.

The Boeing 777 vanished March 8, 2014 en route from Kuala Lumpur to Beijing with 239 people aboard, mostly Chinese nationals.

The cause of its disappearance is unknown and remains one of the greatest mysteries in aviation history.

Amid expectations that the search will soon draw to a close, some families have called for it to be continued indefinitely until the mystery is solved.

Many families continue to allege that only a deliberate cover-up could explain the lack of answers, and some are demanding a reassessment of available data to determine whether authorities are looking in the right area.

Several pieces of debris that apparently drifted thousands of kilometres toward the western Indian Ocean and African coast have been identified as definitely or probably from the Boeing 777, confirming that it indeed must have gone down.

Friday's meeting will be held in the Malaysian administrative capital Putrajaya and will also be attended by Malaysia's Liow Tiong Lai and China's Yang Chuantang.