The woman managed to escape to a bathroom and seek help. Meanwhile the offender sexually assaulted a second woman who was asleep.
She fought him off and fled to seek help from other occupants in the flat and the man left.
Police say the suspected offender was not known to any of the house occupants or party guests.
Forensic examination of the scene had uncovered DNA evidence indicating that the suspected offender was also linked to an unsolved 2016 case in Auckland.
In that case a female, who was drinking in town, was also awoken to the pain of being sexually assaulted by the man in his car.
She managed to push him off, escape and call for help.
Police believe the man had been responsible for at least three sexual violations in the past three years.
The Auckland victim described the car he used was a dark coloured old-school Toyota Hilux Surf off-road vehicle.