A teenager may have found part of missing Malaysia Airlines Flight 370 on a beach in Mozambique.

Casper Lotter said his son Liam found the piece on December 30 near the town of Xai Xai and returned to South Africa with it. The curved piece has a five-digit number on it.

Mr Lotter said his wife contacted Australian aviation authorities last week after another piece was found in Mozambique. He said the authorities said the number indicates it may belong to a Boeing 777.

A South African Civil Aviation Authority spokesman said they will send the part to Australia to be examined.

The Malaysia Airlines Boeing 777 vanished while flying from Kuala Lumpur to Beijing on March 8 2014.

Mr Lotter said he dismissed the item as a "piece of rubbish" that was probably debris from a boat, but 18-year-old Liam insisted on bringing it back to South Africa, convinced it was part of a plane.

"He was adamant he wanted to bring it home because it had a number on it," said Mr Lotter, adding that his son is not an aviation enthusiast but was simply drawn to the piece of debris.

"It just grabbed him for some weird reason."

His son told East Coast Radio, a South African station: "We picked it up and I turned it around and it had like a curve to it. You could see where it'd been pop-riveted almost, like there's holes on the side."

The teenager's research did not yield much until the family heard about another piece of possible plane debris also found in Mozambique, about 186 miles from where he made his discovery.

Australian authorities contacted South African counterparts to arrange to have the new part taken from his home in the town of Wartburg in KwaZulu-Natal, according to South African officials.

"We have arranged for collection of the part, which will be sent to Australia as they are the ones appointed by Malaysia to identify parts found," said Kabelo Ledwaba, spokesman for the South African Civil Aviation Authority.

Last month, Blaine Gibson, a Seattle lawyer and part-time adventurer, found what could be a piece of tail section from the missing Malaysian airlines flight. The piece had "NO STEP" written on it.

The 58-year-old's search for the missing jet has taken him to beaches in the Maldives, Mauritius, Cambodia, Burma and the French island of Reunion, he said. He also travelled to Malaysia to attend a commemorative ceremony held on Sunday by the families of the 239 passengers and crew who were on board the airliner.