The incident happened in Brenchley Gardens between 2am and 3.10am on Sunday 10 November 2019.
The victim, a woman in her late teens, was walking through the park with a man when he is reported to have raped her.
The suspect and victim were not known to each other but had spoken during the evening in a Week Street bar.
On Friday 15 November 2019 a 24-year-old man was arrested on suspicion of rape. He remains in police custody whilst enquiries continue.
Anyone with information concerning the incident is urged to call us on 01622 604 100, quoting crime reference 46/215787/19.