A 40-year-old Melbourne man has been charged with attempting to hijack a Qantas jet following a mid-air drama in which two flight attendants were stabbed with sharpened wooden stakes.

Qantas Flight 1737 grounded at Tullamarine Airport / AAP

Australian Federal Police said the man was also charged with two counts of being a person onboard an aircraft engaged in flight committing an act of violence against a member of the aircraft.

The charges were laid under the Crimes (Aviation) Act 1991 and Criminal Codes Act 1995.

The man was remanded in custody and was due to appear in Melbourne Magistrates Court this morning.

Yesterday passengers and crew on flight 1737 threw themselves at an armed man to stop him crashing their Qantas jet.

Two flight attendants were stabbed in the neck and head by the man, who ran amok with two 15cm wooden stakes.

Two passengers were also hurt as they piled on top of the alleged hijacker to stop him storming the cockpit of the Qantas jet as it flew from Melbourne to Launceston.

Flight 1737 was carrying 47 passengers and six crew at the time.

Witnesses said the man was armed with a silver aerosol can and a yellow cigarette lighter.

Derek Finlay, a Canadian paramedic, was among the first to tackle the alleged hijacker and help the injured chief flight attendant, known to passengers as Greg.

"There were people screaming and crying, and there was a real commotion going on," he told the Herald Sun last night. (Quiet hero relaxed about drama)

"There were large amounts of blood coming out of Greg's head.

"As soon as we realised what was going on, six or seven of us jumped on him (the alleged hijacker).

"He was very determined. By the time he started wrestling with Greg, he had several other people jumping on him."

Passenger Keith Charlton, who also tackled the alleged attacker, praised the efforts of the injured chief flight attendant.

"The fellow Greg, really was a hero . . . if it wasn't for him we could've been in a lot of trouble," he said. "As he was being attacked, he put his head down into the man's chest and he pushed him back down the plane.

"He had two severe injuries to his head – one was on the chin, one was on the top of his head."

At this point about six passengers rushed to Greg's aid.

Passenger Joe Da Costa said: "The steward had a lot of blood on the back of his neck. He was good, very good, very brave."

Mr Charlton was sitting in the third row when chaos erupted about 3pm just as the seatbelt sign was turned off.

He said a man raced past me with his hands raised in the air" armed with sharp stakes. (Wooden stakes elude checks)

From the moment of the attack till he was subdued, the drama lasted 20 seconds.

The alleged attacker plunged the wooden stake into the neck of the hero flight attendant, 38, who confronted him.

The stabbing sent a spray of blood along the aisle.

A female attendant, 25, was slashed across the face as the man closed on the cockpit.

The flight attendants were released from the Royal Melbourne Hospital late last night.

Two passengers were also treated by paramedics at the scene for minor injuries.

"He went bananas. He attacked two people and tried to gain access to the cockpit," an airline industry source said.

Mr Charlton said the man did not speak during the attack.

"He was completely silent," Mr Charlton said.

Australian Federal Police officers arrested the man immediately the flight landed.

AFP officer Stephen Cato said the man tried to seize the Qantas flight 10 minutes after it left Melbourne for Launceston at 2.50pm yesterday.

Agent Cato said no motive had been established and it was unclear how the stakes – which would not have been picked up by metal detectors – were smuggled aboard.

The officer described the passengers who took on the alleged hijacker as "quite heroic".

Transport Minister John Anderson and Qantas chief executive officer Geoff Dixon said they did not believe the attack was an organised act of terrorism.

"Very shortly after take-off . . . the man started to become very threatening," Mr Anderson said.

"He apparently headed for the cabin and seemed to be intent upon trying to force a nasty outcome. If you call an attempt to crash an aircraft, you might call that a hijacking."

Mr Anderson says security machines at Melbourne airport would not have indicated the offender was carrying a weapon.

"What was used could not have been picked up by a weapons detector and to this point in time we've not said to people you cannot take a piece of wood on a plane," he said.

"But plainly any weapon and any intention to use that weapon is very much proscribed by the law.

"We do know that the plane's security was secured, in large part due to the fact that the crew and their training in a security capacity tripped in very effectively."

None of the air marshals used for security on randomly selected Australian flights was aboard.

The cockpit doors were locked during the ordeal, but the plane was not fitted with the enhanced security doors being phased in after the September 11, 2001, attacks in the US.

Passengers have been offered counselling and substitute flights.