POLICE are investigating the sexual assault of a 40-year-old woman by two men near a Ringwood nightclub on Saturday morning.
The woman left Club Ringwood - at the intersection of Oban Road and Maroondah Highway - about 1.30am after being separated from her friends, and was walking along Oban Road when the men approached.
One grabbed her from behind and she was forced to Mullum Mullum Creek - about 300 metres away, near Marilyn Crescent - where they sexually assaulted her.
It is believed the men fled when when the woman's partner came looking for her, calling out her name.
The men were last seen running off along a nearby bike track.
Detectives from the Knox Sexual Offences and Child Abuse Investigation Team are appealing for any witnesses to come forward.
They are particularly interested in speaking to the driver of a taxi which was seen in the area at the time and three young men who were in nearby Peter Vergers Reserve and may have seen the two men.
The men are described as being Caucasian and around 185cm tall, one with blonde hair and the other with black hair. Both were wearing dark coloured tops.
Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppers.com.au