Sex attacker sought after assaults at East Keilor, Maribyrnong, The Tan

Police are hunting a serial offender responsible for a string of indecent assaults in inner and north-west Melbourne this month.

A man in his 30s is believed to have indecently assaulted four women in less than two hours on November 1.

The first was a 46-year-old woman running The Tan track at Birdwood Avenue about 6am.

The next attack occurred just 25 minutes later when the offender exposed himself to a 23-year-old woman at a tram stop on St Kilda Road.

Just after 7am, two women were approached on a walking track in Maribyrnong and one was assaulted before the offender ran off.

Within 20 minutes, he had assaulted another woman as she walked on Clarks Road, East Keilor.

Detectives from the Melbourne Sexual Offences and Child Abuse Investigation Team have released an image of the man they wish to speak to.

He is described as Caucasian with a slim to medium build.