A woman was grabbed and bashed during a sexual assault in an apartment-block laundry in the city's inner south this week, police say.
Detectives have been told that the 40-year-old victim was alone in the laundry on the ground floor of the Coventry Street apartment block in South Melbourne when a man approached her about 8pm on Tuesday.
The man grabbed the woman from behind and bashed her: she was punched to the face before being sexually assaulted, a police spokeswoman said.
The attacker fled the laundry in an unknown direction. Police are unsure about what he was wearing at the time.
He is described as being in his 20s, white, about 180 centimetres tall and having a thin build.
Detectives from the Moorabbin sexual offence and child abuse investigation team have released a computer-generated image of a man they believe can help in their investigation.
Anyone with information is asked to phone Crime Stoppers on 1800 333 000.