A Qantas spokesman said he had been "disruptive and threatening". The spokesman said that staff had tried to calm him down, but when that failed they were forced to take action.
The trouble started about halfway through the three-and-a-half-hour flight, according to Rob, who said that the man - who has not been named - threatened cabin crew and the pilot.
"They brought the guy up to the front of the plane and ... he yelled out and ... of course everybody woke up.
"Then he attacked the guy that was standing beside him, and then the hostess said 'Please help, please help'." Once he had been overpowered and had his hands tied, according to witnesses, he sat quietly at the back of the plane for the rest of the flight.
Rob said: "I don't know what was wrong with him. He was threatening staff, he was threatening the pilot ... it was pretty scary stuff. It ... was quite a violent incident. All of the passengers were pretty upset at the front, there were women crying."
None of the 160 passengers on the flight was injured.
An AFP spokesman said officers had escorted a man restrained in flexi-cuffs off the plane.