Otago Corrections Facility prison director Dave Miller said corrections staff at the prison in Milburn responded quickly to provide first aid to the victim following a prisoner-on-prisoner assault.
Hato Hone St John responded to the incident and transported the man to Dunedin Hospital.
The prisoner was returned to the corrections facility overnight.
"Corrections will also carry out a review into the incident and will ensure all evidence is provided to police," Mr Miller said.
The alleged perpetrator was placed into directed segregation and further disciplinary charges may be laid following police inquiries.
"Many prisoners have long histories of antisocial behaviour, and can behave unpredictably and act without warning.
"Violence in prison is not tolerated and anyone who displays such behaviour will be held to account for their actions, including potentially facing criminal charges."
Mr Miller said corrections would carry out a review of the incident and would give all evidence to police.
