A woman was allegedly raped by a cop after reporting a previous rape at the Saldhana Bay police station.

CAPE TOWN - The Independent Police Investigative Directorate (IPID) has launched an investigation following an alleged rape of a 20-year-old woman at the Saldanha Bay police barracks.

The incident was reported to police earlier this month and the IPID has since taken over the investigation.

The IPID says it's alleged the woman was raped by three civilians during early November.

She reported the incident to police a day later.

The victim was then approached by a policeman who took her to the Saldanha police barracks where he allegedly raped her.

IPID's Moses Dlamini says the circumstances around the incident are not yet clear at this stage and no arrests have been made.

DNA samples have since been taken from the complainant.

The South African Policing Union (Sapu) says it's disturbed by the alleged rape.

SAPU's Joseph Manuel says the law must take its course as incidents of this nature cannot be tolerated.

"This sort of conduct is totally unacceptable."