Women are being warned to exercise in groups around the popular Bay Run in Sydney's inner west after three females were assaulted by a serial sex pest with fang-like teeth.

Police are investigating whether the man with the "unique set of front teeth" who indecently assaulted the trio may have been behind other similar incidents.

Police released a photo taken by an independent witness of a man they believe can assist with investigations into the three assaults on the much-used harbourside running track.

Police have released an image of a man that may be able to assist as investigations continue into three indecent assault of three women on the Bay Run. Credit:NSW Police

Detective Inspector Ned Gligorevic said there were a number of other ongoing inquiries, but so far police have linked one man to incidents involving three separate women.