Blaine Gibson, who has already found possible debris in Mozambique, made the latest discovery on the east coast of Madagascar.

One of the parts resembles an aeroplane seat part. Mr Gibson has sent images of the finds to investigators.

MH370, flying from Kuala Lumpur to Beijing, had 239 people on board when it vanished in March 2014.

Don Thompson, a British engineer who is part of an informal international group investigating MH370, said he thought one piece was from the back of a seat, and the other could be part of a cover panel on a plane wing.

"The seat part I am 99.9% sure on," he told the BBC. "It's the right colour of fabric for Malaysian Airlines. It shows the seat had to have disintegrated to have come away."

Mr Gibson said images of the latest finds had been sent to investigators at the Australian Transport Safety Bureau (ATSB) and to officials in Malaysia.

He said he was ready to hand over the pieces to authorities in Madagascar.

The ATSB confirmed they had received the latest images, and said it was Malaysia that assessed any new leads.

Also on Thursday, an ATSB spokeswoman said they were investigating whether debris found on Kangaroo Island in South Australia may have come from MH370.

Footage broadcast on Australia's Channel Seven showed white wreckage that included the words 'Caution No Step'.

Australia has been leading the search for the missing aircraft, using underwater drones and sonar equipment deployed from specialist ships.

The search, also involving Malaysia and China, has seen more than 105,000 sq km (65,000 sq miles) of the 120,000 sq km search zone scoured so far.

All the debris is being examined in Australia by the ATSB and other experts.

But countries have agreed that in the absence of "credible new information" the search is expected to end in the next two months. (BBC)