A teenage boy caught smoking a bong on a Sydney train proudly boasted he 'didn't give a f***' that he was breaking the law.

The 15-year-old boy was filmed puffing smoke in the carriage while sitting with a friend near the door of the train last June.

He was smoking from a home-made bong fashioned out of a Gatorade bottle, according to The Daily Telegraph.

The teenager was caught on camera sitting in the space between the door with friends on a Sydney train last June

The brazen teenager said he didn't care if passengers caught him smoking weed.

'There were c**ts sitting right outside the door and I opened the door, I've got a billy in my hand and I'm like f*** em' - stay for a cone anyway,' he said.

Transport Minister Andrew Constance condemned the use of drugs on the train.

'We will not tolerate this sort of behaviour and I will be ensuring police investigate,' he said.

'Incidents involving drug use on our trains are rare but we encourage anyone who witnesses this kind of behaviour to alert staff or police.'

A Sydney Trains spokeswoman told Daily Mail Australia it was 'rare' for drugs to be used on the public transport system.

They were smoking from a home-made bong fashioned out of a Gatorade bottle

'We encourage customers who witness any criminal or anti-social behaviour on one of our train services to report it to NSW Police or Sydney Trains staff immediately,' she said.

'We have more than 11,000 CCTV cameras monitoring our network. We also work closely with the NSW Police Transport and Public Safety Command, which is responsible for responding to crime and anti-social behaviour on the rail network.'

A New South Wales Police spokeswoman said police actively patrolled trains to catch people breaking the law.

She said anyone with information about crimes on trains should contact Crime Stoppers.

Daily Mail Australia has contacted Transport NSW and Sydney Trains for comment.