AUSTRALIA has appointed one of its most decorated military figures to help co-ordinate the search for Malaysia Airlines flight 370, as more planes and ships join the hunt.

Prime Minister Tony Abbott says retired Air Chief Marshal Angus Houston, the country's former defence force chief, will lead a new joint agency co-ordination centre (JACC) to be based in Perth.

The headquarters will help communication between international search partners, while trying to keep the families of those on the missing Malaysia Airlines flight informed.

As about 50 Chinese relatives of passengers arrived in Malaysia to press for answers, a specially equipped Australian naval vessel prepared to depart Perth with the task of finding the Boeing 777's black box recorder.

It will leave early on Monday for the vast Indian Ocean search zone, after officials said the first debris picked up by ships combing the area was not from the stricken plane.

"It appeared to be fishing equipment and just rubbish on the (ocean's) surface," said a spokesman for the Australian Maritime Safety Authority, which is in charge of the operation.

Mr Abbott said Air Chief Marshal Houston's new search hub would work with key Commonwealth, state and international stakeholders, including the families and international media.

"There is no one better placed than Angus to co-ordinate and liaise given the quite significant number of countries that all have a stake in this search," Mr Abbott said.

On Sunday, 10 aircraft and eight ships were deployed to the updated search area, 1850km west of Perth.

They will be joined by the Australian defence vessel Ocean Shield, which is fitted with specialist US Navy equipment designed to detect the tiny "pinger" within the plane's black box and to photograph potential debris on the sea floor.

But without a confirmed piece of debris, the ship and crew will be left to scan the horizon with the rest of the search teams before its high-tech equipment can be used.

It had been feared the 30-day life of the black box could expire before the equipment arrives.

But Captain Mark Matthews, the US Navy supervisor of salvage and diving, says the device is certified for 30 days but could last up to 15 days longer than that.

"These are rated to last 30 days, but that is a minimum. In my experience, they do last a little bit longer than that," Capt Matthews said.

"I would say 45 days is the realistic limited expectation."

Australian Navy Commodore Peter Leavy said the focus was still to find debris and confirm it was from flight MH370, then work backwards to a possible crash site.

"The search area remains vast and this equipment can only be effectively employed when there is a high probability that the final location of Flight MH370 is better known," he said.

Flight MH370, with 239 people aboard, disappeared on March 8 after veering sharply off course on the way from Kuala Lumpur to Beijing.

Originally published as Houston to co-ordinate MH370 search