In her complaint to the police, the victim alleged that she was forcibly taken away and sexually assaulted by some men, a district police official told PTI.
The official said the incident took place when the victim was taking a stroll alone along the sea shore in the tourist town of Mamallapuram.
The woman was taken to a hospital for medical examination and the probe is on, he said.
Several persons are being questioned and some of them have been detained, he added.