Men allegedly took turns holding GoPro as they raped a 16-year-old girl.

A young Sydney man facing a possible life sentence has been refused bail for his alleged involvement in the gang rape of a teenage girl.

Tristan Carlyle-Watson allegedly contacted the teenager over Facebook and invited her to the party where he is said to have supplied her with alcohol and cannabis. 

It is alleged that the 16-year-old girl fell in and out of consciousness as she was sexually assaulted by several men after accepting an invitation to attend a party at St Clair.

A bail hearing took place on Wednesday at the NSW Supreme Court that heard the alleged attackers took turns filming themselves sexually assaulting the teenager using a GoPro camera.

It was also heard that Carlyle-Watson was captured on the film laughing.

Justice David Davies said the footage portrayed "what can only be described as a gang rape of the victim when she was sometimes unconscious, and the rest of the time exceptionally inebriated".

Justice Davies also said it was reasonable to infer one of the victim's drinks may have been spiked.

The lawyer representing Carlyle-Watson told the court the footage did not capture his client participating in sexual activity and that the girl's stated memories were unreliable.

"Her first recollection was that she had no idea that she had sex with anyone. That was the first thing that she told her friends," the lawyer said.

"It was only when the police had access to the GoPro that they saw the footage, and made inquiries and spoke to her."

The footage was found after the camera was seized last May during a graffiti crackdown. 

Carlyle-Watson was initially facing one charge of concealing a serious indictable offence.

He has since been charged with further offences including aggravated sexual assault in company and sexual assault.

The charge of aggravated sexual assault in company carries a maximum penalty of life in prison.

The case resumes on Friday at Penrith Local Court.