Police are looking for the man, who forced himself on the 28-year-old woman when she was standing on the corner of Terminus St at Petersham about 1.30am on Thursday.
Police said he tried to sexually assault the woman but she pushed him away and both fled in opposite directions.
The man, aged in his 20s, drove past the woman on Crystal St soon after and tried to speak to her before driving off.
Police have described the man as being of Middle Eastern/Mediterranean appearance with an olive complexion, aged in his 20s with a slim build and a beard.
He was wearing a black polo short with a red collar, cuffed tracksuit pants, a backwards cap and bright red New Balance joggers.
Detectives are urging anyone with information to contact Crime Stoppers on 1800 333 000.
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