Photo: vicpolicenews

Investigators have been told a 48-year-old woman boarded the bus on Patterson Street, Moonee Ponds about 2.30pm on 5 October.

Whilst seated on the bus a man approached the woman and sexually assaulted her.

The woman tried to move away from the man and he followed her to the front of the bus.

She disembarked the bus at the intersection of Sydney Road and Brunswick Road, Brunswick, and the man continued to follow and harass her until she was able to seek help from a member of the public.

He then fled on foot North along Sydney Road.

The man is believed to be aged in his 40s with an olive complexion, short dark hair and a scar on his left cheek.

He was wearing a white shirt and blue jeans and spoke with an accent.

Detectives have released CCTV footage and still images of a man they believe can assist with their enquiries.

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