Experts in France have begun examining an aircraft part that washed up on the Indian Ocean island of Reunion last week to see if it is from Flight MH370.
The wing fragment, known as a flaperon, is from a Boeing 777, the same make as the missing Malaysian airliner.
France has invited Malaysian and Australian aviation experts to Balma to help with the investigation.
Australia’s Deputy PM Warren Truss said the teams may be able to say this week if it came from the plane.
For reasons that remain unclear the Malaysia Airlines plane, with 239 people on board, veered off course on its way from Kuala Lumpur to Beijing in March 2014.
It is believed to have crashed into the southern Indian Ocean – though no confirmed trace has ever been found despite a massive search operation.
The part is being examined under the direction of a judge at an aeronautical test centre run by the French military in Balma, near Toulouse.
Reunion is one of France’s overseas territories.
French and Malaysian experts are attending, Boeing employees and representatives from China – the country that lost most passengers in the disaster.
Jean-Paul Troadec, the former head of the French BEA agency that investigates air accidents, told AFP news agency that the examination would concentrate on two issues – whether the part belongs to MH370 and if so, whether it could provide any information on the final moments of the plane.
Mr Troadec said paint on the wing part – which has already been confirmed as coming from a Boeing 777 plane – was a vital part of the investigation.
“Every airline paints their planes in a certain way… and if the paint used is used by Malaysia Airlines and other companies, there may be more certainty,” he said.
Serial numbers will also be searched for and barnacles on the debris examined.
No other Boeing 777s are thought to have crashed in the region.
The initial examination is expected to last until Thursday but Malaysian officials have been on standby in Kuala Lumpur in case results come through earlier, Reuters reported.
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Mr Troadec cautioned that the analysis was highly unlikely to give any clues as to why the plane went off course.
“One should not expect miracles,” he said.
An Australian-led search for the plane has focused on a vast area of the southern Indian Ocean about 4,000km (2,500 miles) east of Reunion.