A piece of suspected plane wreckage found off the coast of southern Thailand three days ago does not belong to a Malaysia Airlines passenger jet that disappeared almost two years ago, the Malaysian transport ministry says.

The debris does not match those of a Boeing 777 and the part numbers found on the debris were not listed on the Malaysia Airlines’ parts catalogue manual, the ministry said in a statement following an investigation.

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A large piece of curved metal washed ashore in Nakhon Si Thammarat province on Saturday, prompting speculation it might belong to the missing jet, which was a Boeing 777.

Malaysia Airlines Flight MH370 disappeared with 239 people on board during a flight from Kuala Lumpur to Beijing in March 2014.

A piece of the plane washed up on the French island of Reunion in July 2015 but no further trace has been found.

The search, led by Australia and one of the most expensive ever conducted, is focused on a 120,000 square kilometre band of sea floor in the remote southern Indian Ocean.

Earlier this week, Australian authorities searching for the jet said they had lost a deep-water sonar detector being used to scour a patch of the ocean floor.

-with agencies