Heavily armed security officers boarded a Malaysia Airlines plane at Melbourne’s Tullamarine airport after a passenger claiming to have a bomb tried to enter the cockpit shortly after takeoff.

Flight MH128 from Melbourne to Kuala Lumpur, carrying 330 passengers, was forced to make an emergency landing in Melbourne late Wednesday night when a man threatened to blow up the plane.

Police later revealed the man had been released from psychiatric care the same day.

Witnesses described how the man, carrying an black object, went toward the front of the plane shortly after it took off at 11:11pm.

The man was tackled by passengers who overpowered him and tied him up with belts.

The plane landed back at Melbourne just before midnight and was parked in a remote bay.

Heavily-armed police wearing helmets and body armour and carrying rifles boarded the plane and put the man under arrest.

فيديو | لحظة اقتحام القوات الخاصة الأسترالية للطائرة الماليزية #MH128 و القبض على الراكب الذي هدد باختطافها pic.twitter.com/gqq77kI2G9

— عشاق عالم الطيران (@AviationWG) May 31, 2017

Victoria Police later said the incident was not being treated as terrorism and that the man’s object was an electronic device and not a bomb.

Victoria Police originally thought there was more than one terror threat on board Malyasia Airlines flight MH128 to Kuala Lumpur, so they waited up to 90 minutes before special operations officers stormed the plane.

Suspect released from psychiatric care

A 25-year-old Sri Lankan national, living in Dandenong and on a student visa, was arrested early on Thursday morning following the overnight drama.

“He had been released from psychiatric care from the Monash Medical Centre (on Wednesday), and from there, we believe he has purchased a ticket on this plane,” Chief Commissioner Graham Ashton told reporters.

Victoria Police Superintendent Tony Langdon praised the “heroic” actions of the passengers.

“I would say that it would have been quite heroic for the crew and passengers to restrain this person,” Superintendent Langdon said.

He said he believed security measures at the airport were appropriate.

“The circumstances are that the gentleman stated he had a device, and he had a piece of equipment which, for all intents and purposes, is something that everybody would be carrying around on a daily basis,” he said.

He would not go into any further detail about the object, except to say it was an “electronic device”.

“It was quite quickly ascertained it wasn’t an explosive device,” he said.

Police have interviewed passengers about the incident.

“They’d be very concerned. They’re tired. They’ve had their plans disrupted. I can’t praise them highly enough,” he said.

“They’ve been wonderful in their co-operation with us and we just hope that they have a wonderful journey after this.”

The airline stressed that “at no point was the aircraft ‘hijacked’.

‘I’m going to blow up the plane’

Former AFL player Andrew Leoncelli, who was on the plane at the time, told the ABC he was near the front of the plane and saw a man carrying a big object go towards the cockpit and become really agitated.

“I ran to the front and confronted him around the corner and he was there and he was a tall guy, taller than me with a beanie on, wearing dark clothing, dark skin, carrying a giant thing, a very strange-looking thing with antennas coming off it, saying, ‘I’m going to blow the plane up, I’m going to f***ng blow the plane up’.”

He said the man then ran to the back of the plane, where he was overpowered by other passengers.

“Staff grabbed the object, which we’re not sure what it was, he was claiming to blow the plane up with, and walked it back to the front of the plane.”

The man was subdued by passengers. Photo: Twitter

The plane was parked in a remote bay after it landed. The Australian Federal Police said they were investigating the incident.

“There appears to be no imminent threat to passengers, staff or public and the investigation is ongoing,” Senior Constable Adam West said.

The airport was closed during the incident but has now reopened.

Fairfax reported that in air traffic control audio posted online, a male voice can be heard saying: “We have a passenger trying to enter the cockpit.”

About three minutes later, the same male voice can be heard saying the passenger was “claiming to have an explosive device, tried to enter the cockpit, has been overpowered by passengers”.

“However we’d like to land and have the device checked,” the voice reportedly said.

Arif Chaudhrey was also onboard the flight and helped stop the man.

“Staff screamed ‘help, help help’ … I was about four to five seats from where it happened,” Mr Chaudhrey told the ABC.

“A couple of us guys quickly jumped to grab that guy.

“The staff [got] a spare seatbelt so we handcuffed him at the back, his legs and hands, and put his face on the floor.”

In a statement, Malaysia Airlines said affected passengers would be accommodated at hotels.

“They will be offered travel on the next available flight or on other carriers.”

All other flights were diverted to Avalon, near Geelong, during the drama as Melbourne Airport was put into lockdown.

– With agencies