Crew members on a Vietnam Airlines flight from Sydney to Ho Chi Minh City on Thursday had to tie up a Vietnamese-Australian man after he resisted their order and locked himself inside a toilet to smoke.
The 27-year-old was also fined VND4 million (US$183) for the violation. .
He went into the toilet to smoke after three hours into the flight.
The safety system detected the smoke and some crew members asked him to stop and return to his seat.
But he fought back, locked the door and continued to smoke.
The crew members had to ask a passenger to help restrain him and seize his cigarettes and lighter.
They tied him up and kept him at the back of the plane for the rest of the journey.
His family said he had depression and they were bringing him to Vietnam for treatment.