A 27-year-old woman contacted emergency services in the early hours of Sunday August 2 saying she had been attacked on Tudor Close, Brixton Hill.
She told officers a man she didn’t know approached her just before 2.30am near a bench on the road and dragged her by the arm into a secluded area where he raped her.
The suspect is described as black and in his mid-20s.
The London Ambulance Service were called to the scene and she was taken to a Haven Sexual Assault Referral Centre.
Detectives from the Sexual Offences, Exploitation and Child Abuse Command are now investigating.
So far, no arrests have been made.
Detective Inspector Michael Murfin said: “This is very serious incident and naturally the victim is very distraught.
“Specialist officers are currently providing assistance to her and are seeking any witnesses or information that might assist in their investigation.”
Any witnesses to the assault, or anyone with information, is asked to call police on 020 8721 4106 or via the police non-emergency line on 101.
Alternatively, they can contact Crimestoppers anonymously on 0800 555 111.