Police have released a CCTV image following investigations into an alleged incident on a train last year.
Just before midnight on Friday 23 November 2018, police have been told a man in the standing area of a train carriage travelling between Green Square and Wolli Creek committed an act of indecency.
Shortly after, the man moved to an upstairs carriage and sat next to a woman who appeared to be asleep, before he committed an act of indecency which was witnessed by another commuter.
The alleged incident was reported to officers from the Police Transport Command, who commenced an investigation.
Following inquiries, officers have released a CCTV image of a man who may be able to assist with inquiries.
He is depicted as being of Caucasian appearance, believed to be aged in his 50s, of large build with short grey hair.
The man is shown wearing blue jeans and a light coloured short sleeve shirt.
Police are urging anyone with information, or anyone who knows the identity of the man to come forward.
Anyone with information about these incidents is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au. Information is treated in strict confidence.