Police investigating an alleged rape on Boxing Day in Kaitangata, south Otago, say a suspect is in hospital after being attacked by associates of the victim.

The victim, a 26-year-old South Otago woman, was attacked at a Kaitangata home at 7am on Sunday. Kaitangata is 10km southeast of Balclutha.

The suspect was known to the victim and was staying at the address after an overnight party.

Police are also investigating a serious assault on the suspect, who required surgery on a broken jaw. Officers from Balclutha, Owaka, Clinton, and Dunedin are working on the case.