A Malaysian government investigation team has found that both pieces of debris are consistent with panels from a Malaysia Airlines Boeing 777 aircraft, said Australia's minister for infrastructure and transport, Darren Chester.
"The analysis has concluded the debris is almost certainly from MH370," he said.
"That such debris has been found on the east coast of Africa is consistent with drift modeling ... and further affirms our search efforts in the southern Indian Ocean," Chester said.
Flight MH370 disappeared with 239 passengers and crew on board shortly after taking off from Kuala Lumpur bound for Beijing in March 2014.
A white, meter-long chunk of metal was found off the coast of Mozambique this month by a U.S. adventurer who has been carrying out an independent search for flight MH370. It arrived in Australia for testing earlier this week.
The debris was examined by investigators from Australia and Malaysia, as well as specialists from Boeing, Geoscience Australia and the Australian National University in Canberra.
Malaysia said this week it would send a team to retrieve a piece of debris found along the southern coast of South Africa to check whether it could also belong to MH370.
The jet is believed to have crashed in the Indian Ocean and an initial search of a 60,000 sq km (23,000 sq miles) area of sea floor has been extended to another 60,000 sq km.
A piece of the plane's wing washed up on the French Indian Ocean island of Reunion, on the other side of Madagascar, in July 2015. So far only that piece, known as a flaperon, has been confirmed to belong to the missing plane.