It is alleged the woman was in the front yard of a home in Rivercoast Road when the incident occurred about 2am.
The victim, a 43-year-old Werribee South woman was conveyed to hospital with life-threatening injuries.
Detectives have investigated the circumstances surrounding the incident, which is believed to have occurred following a dispute.
A male at the scene who identified himself as the woman’s brother said an argument broke out at the party between a man and a woman towards his sister, who was doused in petrol and set alight.
A 43-year-old Werribee South man has been charged with attempted murder, conduct engendering life, intentionally cause serious injury and recklessly causing serious injury.
He has been remanded in custody and will appear at Melbourne Magistrates’ Court on 29 December.
A 45-year-old Werribee South woman was released pending further enquiries.