Malaysia Airlines Flight MH370 disappeared in March last year enroute from Kuala Lumpur to Beijing with 239 passengers and crew on board.

Investigators in France ascertained that the barnacle-covered debris, a 2-2.5 meter (6.5-8 feet) wing surface known as a flaperon, belonged to MH370 just days after Malaysia identified it as being part of the same model, a Boeing 777.

The confirmation brings some closure to the relatives of those on board but does not shed any light on what happened to the airliner.

"I would like to assure all those affected by this tragedy that the government of Malaysia is committed to do everything within our means to find out the truth of what happened," Najib said.

The plane piece washed up last Wednesday on Reunion, a volcanic island of 850,000 people that is a full part of France, located in the Indian Ocean near Madagascar.

Reunion is roughly 3,700 km (2,300 miles) from the broad expanse of the southern Indian Ocean off Australia where search efforts have focused, but officials and experts said currents could have carried wreckage that way, thousands of kilometers from where the plane is thought to have crashed.

Malaysia Airlines said in a separate statement that the relatives of passengers and the crew had been informed.

The airline said the discovery was a major breakthrough in resolving the disappearance of MH370.

"We expect and hope that there would be more objects to be found which would be able to help resolve this mystery," it added.