PERTH - The Australian Transport Safety Bureau ruled out Thursday any link between material found on a beach in southwestern Australia and the missing Malaysia Airlines jet.
Debris described as "unidentified material" was found Wednesday on a beach near Augusta, more than 300 kilometres (180 miles) south of Perth, by a member of the public and handed to police.
The ATSB decided to examine photographs of the material to determine whether it was linked to the search for the missing Boeing 777.
Photographs were also provided to the Malaysian investigation team.
However ATSB chief commissioner Martin Dolan scotched any hope of a breakthrough.
"We've carefully examined detailed photographs that were taken for us by the police, and we're satisfied that it's not a lead in terms of the search for MH370," Dolan told ABC radio.
"We want to pursue every possible lead that will help us find MH370 but sadly this is one that isn't going to help that search," he said.
"We do encourage everyone who thinks they have viable leads in relation to the aircraft to contact the ATSB."
Dolan had Wednesday night declared the material, apparently sheet metal with rivets, "sufficiently interesting for us to take a look at the photographs".
However he had added a note of caution. "The more we look at it, the less excited we get."
As frustrations grow at the failure to find any trace of MH370, Australia's Joint Agency Coordination Centre (JACC)said Thursday an underwater search with an unmanned mini-sub was almost finished.
"Bluefin-21 has now completed more than 90 per cent of the focused underwater search area.
"No contacts of interest have been found to date," the statement said.
The sonar Bluefin device was currently completing its 12th mission, JACC said, in an area defined as a circle of 10-kilometre (six-mile) radius around a signal detected on April 8.
If the completed Bluefin hunt draws a blank officials say the operation will move to a new phase and likely need bigger equipment.
The airliner with 239 people aboard was flying from Kuala Lumpur to Beijing on March 8 when it mysteriously diverted.
It is thought to have crashed into the remote Indian Ocean off Western Australia.
A surface search involving a fleet of ships and military aircraft would depend on the weather on Thursday, JACC said with the forecast for heavy rain and low cloud as Tropical Cyclone Jack moves south.
The visual hunt covers an area totalling about 49,567 square kilometres (19,100 square miles) some 1,584 kilometres northwest of Perth.