The incident happened in the zero hours of Tuesday on Poonamallee High Road near Anna Arch when the victim was waiting after ordering food at an eatery.
Three men who appeared drunk allegedly asked the victim for directions to a nearby toilet and when she said she did not know, the trio reportedly raised voice on her.
When she told them she was a police personnel, the accused ignored her words and groped her before leaving the spot. One of them told the victim that he too was a police personnel attached to Aminjikarai police station.
The victim rushed to Aminjikarai police station and lodged a complaint about the incident.
Aminjikarai police are combing the CCTV footage to identify the suspects.