Between 7.30pm and 10pm last night, the 15-year-old alleged victim had been socialising with a number of people near to the skate park area in Exhibition Park, Newcastle.
She then left the area with a male member of the group who she did not know, at which point she has been raped.
An investigation has now been launched by detectives to identify the person responsible and specialist officers are currently supporting the teenage girl in this case.
Police are continuing enquiries today and have asked anyone who was in the area at the time, and may have information about the incident, to get in touch.
The man is described as white, a teenager, of slim build, with black hair and trimmed facial hair.
He was wearing black jogging bottoms and a dark Northface jacket with the hood up.
The man, or anyone who may know him, is asked to contact police on 101 quoting log 1424 24/03/17 or Crimestoppers anonymously on 0800 555 111.