Dandenong Sexual Offences and Child Abuse Investigation Team detectives are appealing for public assistance following a series of wilful and obscene exposure incidents in Springvale South.
On three occasions the victims have been walking through Burden Park, Springvale South.
The first incident occurred in November 2017 with the second incident occurring in April.
The most recent reported incident happened on 12 June and the man was last seen walking along Janine Road, Springvale South.
On all three occasions the offences were committed between 4-4.30pm.
Detectives have been told the offender would approach the victims, aged from 13 to 15, and expose himself before committing an indecent act in front of them.
Investigators have released an image of a man they believe may be able to assist with their enquiries.
The man is perceived to be Asian, with long black hair and a heavy build.
He was wearing a grey windcheater, black tracksuit pants with two white stripes at the ankles and black shoes with white soles.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report online at www.crimestoppersvic.com.au