It is the latest development in efforts to solve the mystery of the aircraft, which went missing in March 2014.
The plane, flying from Kuala Lumpur to Beijing, had 239 people on board when it vanished.
It is presumed to have crashed into the sea after veering off course.
Three ships are searching a 120,000 sq km area of the southern Indian Ocean but have so far found no trace of the plane.
Five pieces of debris have been confirmed as definitely or probably from the plane.
Each was found thousands of miles from the search zone, though within the area models of ocean currents have indicated debris could wash up.
All the debris is being examined in Australia by the Australian Transport Safety Bureau (ATSB) and other experts.
They use manufacturing marks on the pieces as well as samples of marine ecology like barnacles to help confirm whether they are likely to have come from the missing Boeing 777.
Speaking on Thursday, Malaysia’s Transport Minister Liow Tiong Lai said the team had “confirmed that both pieces of debris from South Africa and Rodrigues Island are almost certainly from MH370”.
The ATSB also said both sections were “almost certainly” from 9M-MRO, which is the plane’s registration.
No other 777 has ever crashed in the southern hemisphere, and none has reported missing pieces.
The ocean search, involving Australia, Malaysia and China, has scoured more than 105,000 sq km of seafloor so far, much of it areas which have never been explored before.
But the countries have agreed that in the absence of “credible new information” the search will end by the middle of the year.