It’s understood the assault took place shortly after midnight in the St. George’s Gardens area of Belfast.
Detective Sergeant Gary Chambers said: “We are keen to identify and speak to two males we believe may be able to assist us with our enquires.
“It is believed these two male witnesses were walking along St. George’s Gardens in the direction of Sandy Row before the incident occurred and had spoken to the male suspect and female victim involved in this assault.
“We are also appealing for witnesses and would like to hear from anyone who was in the area during the early hours of Wednesday 12th July and who may have witnessed a distressed female or anything else unusual.
“Detectives can be contacted at Ladas Drive by calling 101, quoting reference 152 of the12/07/17.
Or, alternatively if someone would prefer to provide information without giving their details they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.”