PM Najib Razak said experts examining the debris in France had "conclusively confirmed" it was from the aircraft.

However investigators have stopped short of confirming the link, saying only that it is highly likely.

Australia says it remains confident it is searching in the right area.

The Malaysia Airlines plane was travelling from Kuala Lumpur to Beijing on 8 March 2014 when it vanished from radar. It had 239 people on board.

The debris found on the remote French island in the Indian Ocean a week ago - a wing part known as a flaperon - was the first possible trace.

The part was flown to a military laboratory in the French city of Toulouse where experts were carrying out their second day of tests on Thursday.

Following the earlier tests, Mr Najib held a news conference in Kuala Lumpur to announce that investigators had "conclusively confirmed that the aircraft debris found on Reunion Island is indeed from MH370".

This would "at least bring certainty to the families", he said.

Some of the relatives, meanwhile, have expressed frustration with the lack of certainty.

"It's somewhat frustrating," Sara Weeks, whose brother was on the flight, told Fairfax media from New Zealand. "Why not wait and get everybody on the same page so the families don't need to go through this turmoil?"

Most of the passengers were Chinese - many of their relatives have consistently questioned the official view that the plane crashed.