Bayside Sexual Offences and Child Abuse Investigation Team detectives are investigating a sexual assault in Mordialloc earlier this year.
Police have been told a 41-year-old woman attended a licenced venue on Main Street about 11pm on Saturday, 29 June.
While she was inside the venue, an unknown man approached the woman and sexually assaulted her.
Detectives believe the woman confronted the unknown man, before he fled the scene.
Investigators have released an image and CCTV of a man they believe may be able to assist with their enquiries.
He is described as being approximately 40-45 years old, with tanned skin, a solid build and bald.
He was seen wearing a green hooded jumper, blue jeans and black shoes.
Anyone who witnessed the incident, has dashcam/CCTV footage or information is urged to contact Crime Stoppers on 1800 333 000 or make a report online at www.crimestoppersvic.com.au