CANBERRA, Australia -- Australian officials said Thursday that after examining detailed photographs of unidentified material that washed ashore in the southwestern part of the country they are satisfied it is not a clue in the search for the missing Malaysian plane.

The Australian Transport Safety Bureau has advised search co-ordinators that the material, which washed ashore 10 kilometres east of Augusta in Western Australia, is not from missing Flight 370, according to a statement from the Joint Agency Coordination Centre.

Martin Dolan, chief commissioner of the safety bureau, told The Associated Press Wednesday that an initial analysis of the material -- which appeared to be sheet metal with rivets -- suggested it was not from the plane.

"We do not consider this likely to be of use to our search for MH370," he said.

Augusta is near Australia's southwestern tip, about 310 kilometres from Perth, where the search has been headquartered.

The search co-ordinationcentre also said Thursday a robotic submarine, the U.S. Navy's Bluefin 21, had scanned more than 90 per cent of the 310-square kilometre seabed search zone off the Australian west coast, creating a three-dimensional sonar map of the ocean floor, but had found nothing of interest.

The 4.5-kilometre deep search area is a circle 20 kilometres wide around an area where sonar equipment picked up a signal on April 8 consistent with a plane's black boxes. But the batteries powering those signals are now believed dead.

Meanwhile, Australian Prime Minister Tony Abbott said Wednesday that failure to find any clue in the most likely crash site of the lost jet would not spell the end of the search, as officials plan soon to bring in more powerful sonar equipment that can delve deeper beneath the Indian Ocean.

Defence Minister David Johnston said Australia was consulting with Malaysia, China and the United States on the next phase of the search for the plane, which disappeared March 8. Details on the next phase are likely to be announced next week.

Johnston said more powerful towed side-scan commercial sonar equipment would probably be deployed, similar to the remote-controlled subs that found RMS Titanic 12,500 feet under the Atlantic Ocean in 1985 and the Australian WWII wreck HMAS Sydney in the Indian Ocean off the Australian coast, north of the current search area, in 2008.

While the Bluefin had less than one-fifth of the seabed search area to complete, Johnston estimated that task would take another two weeks.

Abbott said the airliner's probable impact zone was 700 kilometres long and 80 kilometres wide. A new search strategy would be adopted if nothing is found in the current seabed search zone.

"If at the end of that period we find nothing, we are not going to abandon the search, we may well rethink the search, but we will not rest until we have done everything we can to solve this mystery," Abbott told reporters.

The focus of the next search phase will be decided by continuing analysis of information including flight data and sound detections of the suspected beacons, Johnston said, adding that the seabed in the vicinity of the search was up to 7 kilometres deep.

The search centre said Thursday an air search involving up to 11 planes was planned to examine an area of nearly 50,000 square kilometrescentred about 1,600 kilometres northwest of Perth. The centre said it would first assess weather conditions, which have hampered aerial searches over the past two days. The centre said 11 ships would also join the search.

Radar and satellite data show the jet veered far off course on March 8 for unknown reasons during its flight from Kuala Lumpur, Malaysia, to Beijing. An analysis indicates it would have run out of fuel in the remote section of ocean where the search has been focused. Not one piece of confirmed debris has been found since the massive multinational hunt began.