A man who flashed his penis at a woman on a tram in Melbourne's CBD is being pursued by police.

Police have released an image of a man they believe may be able to assist with their inquiries.

The man boarded a route 57 West Maribyrnong tram outside Flinders Street Station on Sunday, 28 January about 4.30pm.

Investigators have been told he sat opposite a woman and exposed his penis throughout the journey before disembarking at Abbotsford Street in North Melbourne.

Police have released an image of a man they believe may be able to assist with their enquiries.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report to www.crimestoppersvic.com.au.