Plane debris washed up on the French island of Reunion in the Indian Ocean is almost certainly part of a Boeing 777, a Malaysian official and aviation experts said, potentially providing some answers for families of those aboard last year's vanished flight MH370.

Malaysian investigators are due in Reunion on Friday and the object, identified by numerous aviation experts as part of a wing, is then due to be sent to a French military laboratory near Toulouse for checks, French police sources said.

National carrier Malaysia Airlines was operating a Boeing 777 on the ill-fated flight, which disappeared in March last year en route from Kuala Lumpur to Beijing in one of the most baffling mysteries in aviation history. It was carrying 239 passengers and crew.