A prison inmate is in hospital with serious injuries after an assault police say was linked to the Black Power gang.
Detective Sergeant Hayden Smale said the man was attacked around 2.30pm on Fridayat the Otago Corrections Facility, south-west of Dunedin.
"The victim, an inmate at the prison, is currently in a serious but stable condition at Dunedin Hospital as a result of injuries he received during the assault," Smale said.
His family have been informed.
"The assault happened in an exercise yard at the prison and involved members of the Black Power gang," Smale said. "The victim is not linked or involved with this gang."
Prison director Lyndal Miles said staff responded immediately to provide the victim with medical assistance and he was transported to hospital.
"The alleged perpetrator was removed from the unit and placed on directed segregation.
Police attended the site, and are investigating the circumstances of the incident," Miles said.
Miles said violence in prisons was "unacceptable" and the prevalence of gangs and their influence was contributing to the rate of prison violence.
"Prisoners who use violence will be held to account for their actions," she said.
A team of 10 police staff from the Dunedin and Balclutha CIB are investigating the assault.
Smale said it was too early to comment on the nature of any charges that may be laid or the number of people involved in the assault.