The two-metre long flaperon, a wing component, was found yesterday on Reunion Island off the east coast of Africa.
Malaysia's Deputy Transport Minister Abdul Aziz Kaprawi said it was "almost certain" that the wreckage was from a Boeing 777 aircraft.
France's air crash investigation agency is studying a piece of plane debris.
Boeing officials conducted an initial assessment of the debris using photographs.
The source stressed the observations are preliminary.
Australia's Transport and Infrastructure Minister Warren Truss said the discovery was "a very important development" in the hunt for MH370, and it was feasible debris could have floated to the French island of La Reunion.
"The Reunion islands are a very long way from the search area but it is consistent with the work that has been done in identifying the current search area, the satellite interpretations of the route path that the aircraft is expected to have taken," Truss said.
Malaysia's Minister of Transport Liow Tiong Lai told reporters yesterday that he had received information from his colleagues in Malaysia about the wreckage that has been spotted in La Reunion.
"I have sent a team to verify the wreckage. Anyway we need to verify," Liow said following a UN Security Council meeting on another Malaysia Airlines flight MH17, which crashed in July 2014 in Donetsk, Ukraine.
The Boeing 777-200 plane of Malaysia Airlines went missing on March 8, 2014, an hour after taking off from Kuala Lumpur for Beijing.
