Police are investigating a sexual assault on a Port Melbourne-bound tram in Kew on 8 February.
Investigators have been told a man boarded the number 109 tram on Cotham Road about 8.30am.
He sat opposite the 12-year-old male victim who was sitting with a group of boys and sexually assaulted him.
Investigators are keen to speak to anyone on the tram at the time who may have witnessed the incident.
The victim exited the tram at the Kew Junction and the man remained on the tram.
The man is described as Asian in appearance, aged 50 to 60-years-old and was wearing a cream jacket with a parrot on the left breast.
Investigators have released a face fit image of a man they wish to speak to in relation to the incident.
Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au