Investigators were Tuesday examining two more pieces of debris for clues to the fate of Malaysia Airlines flight MH370, along with marine life found on two other items which "almost certainly" came from the lost jet.

The latest two pieces -- one found in South Africa and another on the Indian Ocean island of Mauritius -- were brought to the Australian Transport Safety Bureau's laboratories for testing last week.

"Investigators from the ATSB and the Malaysian authorities are currently examining those two pieces for details which would serve to identify them as coming from a Boeing 777," the bureau said in a statement.

"And in particular for any details which might serve to link the debris as coming from MH370."

Two parts found on beaches in Mozambique along its Indian Ocean coast have already been identified as "almost certainly" from the missing plane.

READ: Mozambique debris 'almost certainly from MH370': Australia

READ: Debris reaches Australia for MH370 analysis

Australia is leading the search in the remote southern Indian Ocean, believed to be the final resting place of the plane which disappeared en route from Kuala Lumpur to Beijing on March 8, 2014 carrying 239 passengers and crew.

Last year a wing part recovered from the Indian Ocean island of Reunion, which neighbours Mauritius, was confirmed as coming from the jet.

Since then two more items found about 220 kilometres (140 miles) apart from each other in Mozambique in December 2015 and February 2016 have been examined.

The ATSB confirmed Tuesday earlier statements that both pieces "almost certainly" came from the Malaysian Airlines Boeing 777 aircraft operating as MH370.

The first part, which had a number stencilled on it, was identified as a segment from a Boeing 777 flap track from the right wing, with the stencilling on it conforming to that used by Malaysia Airlines.

The second part, which had the words "No Step" on it, was identified as a segment of a Boeing 777 horizontal stabiliser panel. Its stencilling was also consistent with that used by the carrier, the ATSB said.

Both pieces were also examined for "marine ecology and remnants of biological material" which could provide clues to their sea journey.

"Visible marine ecology was present on both parts and these items were removed and preserved," the report said.

"At the time of writing, ongoing work was being conducted with respect to the marine ecology identification as well as testing of material samples.

"The results from these tests will be provided to the Malaysian investigation team once complete."

The ATSB said the pieces found in Mozambique would be returned to Malaysia this week.