A prisoner is in hospital after being "seriously assaulted'' at the Otago Corrections Facility.
A St John spokesman said a 32-year-old with serious injuries was transported from the facility to Dunedin Hospital by helicopter at 10.20am on Saturday.
Facility prison director Dave Miller said staff acted immediately to stop the assault by another prisoner.
"Police have been notified of the assault and are investigating.
"Corrections will also carry out a full investigation into the incident, and will ensure all evidence, including CCTV footage, is provided to police.''
