A 31-year-old man detained at Australia's offshore processing centre on Manus Island has been charged with raping a young woman in the provincial centre of Lorengau, Papua New Guinea police say.

Manus Province commander David Yapu said the accused was alleged to have met his 18-year-old victim in the town, before taking her to the nearby Harbourside hotel and raping her multiple times.

"The victim suffered loss of blood until she managed to escape from the room," Mr Yapu told Fairfax Media. The incident occurred on January 17.

The victim attempted to reach safety at a relative's house but "fainted" at the side of a river until she was rescued by a passersby, he said. She was then taken to Lorengau General Hospital for treatment.