The new piece of debris, discovered by a South African family, measures about 1 metre by 0.5 metres, with a curly surface and the digits 676E7 visible. It will be transported to Australia for examination, the authority said.
This is the second piece of debris suspected to be from the missing flight found in Mozambique, after a one-metre long section was discovered in the same area last week.
Australia is the country in charge of analysing any debris related to the flight.
Malaysian Airlines Flight MH370 disappeared on March 8, 2014, en route from Kuala Lumpur to Beijing, with a total of 239 passengers and crew on board.