A woman has encountered a man masturbating before her for the second time in a month in a park in Sydney's inner west, police say.

The woman was walking on a track in Glebe's Jubilee Park about midday on Friday when she saw the man committing the indecent act.

Police believe this man can help with their investigation into the incident in Jubilee Park, Glebe. Credit:NSW Police

It is believed the same man masturbated in front of the woman at that location in late February.

Inspector Renee Holmes of Leichhardt police said the incident had "distressed" the woman and urged anyone who knew the man to call CrimeStoppers.