Three teens will face court after allegedly sexually assaulting an 18-year-old woman in Sydney's west at a party on New Year's Eve.
Police allege the teenagers, one aged 17 and two aged 18, sexually assaulted the young woman in a bedroom of a unit during the party in Prospect on Saturday night.
Concerned friends contacted officers on Sunday to alert officers to the alleged attack, police said in a statement on Monday.
Following inquiries, the two 18-year-old men were arrested at the unit, while the younger teen attended Blacktown Police Station a short time later.
Each of the teens has been charged with aggravated sexual assault. They have all been refused bail.
The alleged victim was taken to hospital and has since been released.
The trio will face court on Monday.