KUALA LUMPUR, Dec 9 — A 25-year-old Sri Lankan man faces up to 20 years jail in Australia after admitting to a forced takeover attempt of a Malaysia Airlines flight out of Melbourne last May.

"I plead guilty, your honour,” Manodh Marks told Magistrate Simon Zebrowski through an interpreter at the Magistrates’ Court in Melbourne to a single charge of trying to take control of an aircraft, the Australian Associated Press reported.

Described as having been diagnosed with mental illness, Marks was initially slapped with multiple serious offences including a more serious charge of attempted hijack of an aircraft, punishable with a lifetime jail sentence.

He was also reported to have been charged with reckless conduct endangering aircraft safety, by attempting to enter the cockpit and threatening to detonate an explosive, and a third charge of threatening to destroy, damage or endanger the aircraft's safety, or to kill or injure anyone on board, which prosecutors dropped in a plea deal.

He has been remanded in custody to face a plea hearing at the Melbourne County Court next April with no request for bail being recorded.

According to Australian news reports, Marks bought a ticket and boarded Flight MH128 bound for Kuala Lumpur on May 1, the same day he was released from psychiatric care.

He was overpowered by fellow passengers on the flight after trying to enter the cockpit and claimed to have an explosive on board.

The pilot turned the plane carrying 337 passengers around after the flight was disrupted.

Marks was subsequently arrested at the Melbourne Airport. No explosives were found on board the plane.