Dutch cyclist Mathieu van der Poel has left Australia after pleading guilty in Sutherland Local Court yesterday to assaulting two teenage girls in Sydney, his lawyer has said.

The incident occurred the night before the men's World Championship road race, which Van der Poel had been among the favourites to win in Wollongong on Sunday but dropped out early.

Lawyer Michael Bowe said facts tendered to the court detailed how the cyclist was repeatedly woken up in the middle of the night by two young girls doing knock-and-runs.

But then Van der Poel took matters into his own hands.

"He opens the door, then they dart back to their room where the door is open," Mr Bowe told ABC Radio.

"He follows them in there. He is telling them he is trying to race the next day, to be quiet. They have been annoying him.

"He has got his hands out and collides with her. Basically, that's the overall of the facts."

Mr Bowe said he assumed the parents of the teenage girls came home and made a complaint to the night manager. Then the police turned up.

The Novotel Brighton-Le-Sands, where the cyclist was staying, would not comment on the incident.

Tried to race on two-hours sleep

The lawyer said Van der Poel lined up and started the 270-kilometre race with about two hours of sleep but withdrew in the early stages.

"He's probably had best case scenario two hours sleep. Not a great way to be lining up for a world championship," Mr Bowe said.

Mr Bowe said his client, who had now left the country, felt as though he let down his team and his country. 

"This is the only race during the whole season or year that you are representing your country," he said. 

"I think he is pretty resilient, but he was shattered. When he got convicted you, could see his girlfriend was crying."

The 27-year-old was convicted of two counts of common assault and fined $1,500.

The organisers of the Wollongong 2022: UCI Road World Championships declined to comment.