Police responded to the report on Tuesday, September 12 at 2pm and were called to Mitcham Town Centre.
The alleged rape occurred on a roundabout off Park Lane in Croydon.
Police have said that specialist officers are supporting the victim.
A crime scene has been put in place on the roundabout and investigations continue.
No arrests have been made at this stage.
The police are requesting any witnesses or individuals with information to come forward and contact police on 101 quoting CAD 9314/12Sep.
A spokesperson for Metropolitan Police said: “Police were called to Mitcham town centre at 14.00hrs on Tuesday, 12 September to a reports of a rape of a woman.
“Officers attended. It was reported the rape of the woman, aged in her 20s, took place on a roundabout off Park Lane, Croydon.
“The woman is being supported by specialist officers.
“A crime scene has been put in place.
“There have been no arrests. Enquiries continue.
“Any witnesses or anyone with any information is asked to call police on 101, quoting CAD 9314/12Sep.”
