Police have launched a fresh appeal for information about a person of interest in an alleged sexual assault in Sydney's inner west, after releasing CCTV footage from the lead-up to the alleged incident.

A 27-year-old woman said she was approached by an unknown man on Terminus Street in Petersham about 1.30am last Thursday.

Police are searching for a man over an alleged sexual assault in Sydney's inner west. Credit:Nine News

Police were told the man forced himself on the woman, and attempted to sexually assault her. After pushing him away, she fled down Crystal Lane West only for the man to follow her and push her to the ground.

She says he indecently assaulted her before running away.