Transit Crime Investigation Unit detectives are appealing for public assistance after an incident on a bus in Dandenong last month.
It is believed a man was onboard the 850 bus travelling from a train station in Dandenong towards Brandon Park when he exposed his genitals to a female passenger about 12.50pm.
It is understood the man got off the bus near Princess Highway shortly after.
Police have released an image of a man they wish to speak to in relation to the matter.
He is perceived to be of Pacific Islander appearance, with a heavy build and short dark hair.
Anyone who recognises the man, or has information that could assist police with their enquiries is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au