KUALA LUMPUR, June 1 — Fellow travellers on Malaysia Airlines Flight MH128 overpowered the passenger who tried to enter the cockpit and claimed to possess an "explosive device” last night.

This was disclosed by aviation news correspondent Brendan Grainger on Twitter where he also described the incident as an "attempted hijacking”.

"Armed law enforcement have boarded Malaysia Airlines flight #MH128 after a security incident at Melbourne Airport,” Grainger said in a subsequent tweet.

The pilot of the Kuala Lumpur-bound MH128 aborted the flight after the alleged hijacking attempt and returned to Melbourne Airport shortly after take off.

MAS later stressed that the flight was not hijacked at any time.

According to news.com.au, police sweeping the plane concluded that there was no bomb on board, although other passengers reported that the man had possessed a "device”.

All other passengers have since disembarked without any reported casualties.

Melbourne Airport remains in a lockdown over the incident and all flights headed there have been diverted to other airports.

The incident is the latest involving the Malaysian airline that is still missing MH370 that disappeared in 2014 and had MH17 shot down in Europe a year later.