A piece of debris found off the southeast African coast that could be from a missing Malaysia Airlines flight is being sent to Australia for testing, officials said on Thursday, two years after the plane carrying 239 people disappeared.

A white, metre-long chunk of metal was found off the coast of Mozambique earlier this week by a US adventurer who has been carrying out an independent search for Malaysia Airlines flight MH370.

The debris will be tested by officials in Australia, with help from Malaysian authorities and representatives of manufacturer Boeing Co.

"It is too early to speculate on the origin of the debris at this stage," Australian Minister for Infrastructure and Transport Darren Chester told parliament.

However, the piece was found in "a location consistent with drift modelling commissioned by the Australian Transport Safety Bureau", he said.

Chester's comments added to a fresh sense of optimism after Malaysia's transport minister, Liow Tiong Lai, said on Wednesday there was a "high possibility" the metal chunk belonged to a 777 jet, the same type of aircraft as MH370.

Flight MH370 disappeared on March 8, 2014, with 239 passengers and crew on board shortly after taking off from Kuala Lumpur bound for Beijing.

It 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.

Chinese Foreign Ministry spokesman Hong Lei said he had "noted" the report about the new possible piece of debris.

"We will closely track the development of the situation, and maintain close contact with relevant sides. We will also work with relevant countries to make great efforts to continue the search work for MH370," he told reporters in Beijing.

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.

Voice370, a group representing families of those on board the missing plane, said the discovery meant the search must focus on the coastlines of Mozambique and Madagascar.

"Debris fields, though subject to some degree of dispersal by the elements, generally tend to make landfall in close proximity," the group said in a statement. – Reuters