The chief co-ordinator of the Joint Agency Co-ordination Centre, retired Chief Air Marshall Angus Houston, gestures as he speaks during a press conference in Perth, Australia. File picture: Rob Griffith

Sydney -

Officials from Australia, Malaysia and China will meet in Canberra on Monday to plot the next phase of the search for a Malaysia Airlines plane thought to have come down in the Indian Ocean.

Flight MH370 vanished on March 8 an hour into a night flight from Kuala Lumpur to Beijing with 239 people on board, most of them Chinese citizens.

One of the biggest searches in aviation history has yet to come up with a trace of the missing Boeing 777.

In the last tally, there had been 334 search flights and 4.5 million square kilometres of ocean scoured. Over 400 square kilometres of ocean floor had been gone over.

Aviation experts and crash investigators will also be in the Australian capital to draw up proposals for commercial operators who are likely to take over.

The officials convene as the UN Navy committed a submersible sonar scanner for another month of searching in an area around 1 500km north-west of Perth where searchers are confident the plane went down.

The patch was a circular area with a radius of 10km from the point where the last acoustic signal was picked up April 8 by a ship towing an emergency beacon locator listening for black-box pings.

Angus Houston, who is co-ordinating the search from Perth, told reporters in Kuala Lumpur on Friday that the search could take up to 12 months.

Houston, a former Australian armed forces chief, said the Canberra meeting was to “formalise the way ahead”.

He said: “We are totally committed as three nations, I believe, to finding MH370 and I'm confident that with an effective search we'll eventually find the aircraft.”

A new undersea search area, 700km long and 80km wide, has been defined for commercial operators who will bring in a submersible able to go down deeper than the US Navy Bluefin-21.

The Bluefin, which is limited to a depth of 4 500m and had to resurface to download sonar readings, trawled over 400 square kilometres of ocean floor without success.

It is likely to be replaced with a submersible that can dive to 6 000m and stream data live to the ship towing it.

Last month Prime Minister Tony Abbott said that bringing in commercial operators would cost A$60-million ($56-million) and that Australia would be “seeking some appropriate contribution from other nations involved but we'll ensure that this search goes ahead”.

The Australians were thought to be likely to ask for contributions at the Canberra meeting. - Sapa-dpa