A power outage which cut television and heating for some prisoners sparked a seven-hour protest and resulted in the Otago Corrections Facility being locked down on Saturday.
The Milburn-based prison was locked down at 10.30am when five prisoners staged a protest after power was cut to their unit, Prison Manager Reti Pierce said.
The five prisoners took part in the "passive protest" in the central yard of their accommodation unit, while other prisoners were securely detained, he said.
The Department of Corrections was tight-lipped over the reason for the protest.
However, the Otago Daily Times understands the prisoners were unhappy over having no heating or television to watch.
The $218 million prison attracted criticism when it opened in 2007 for its underfloor heating and each wing having a flat-screen television.
Each prisoner is also allowed his own television set in his cell, subject to approval.
Mr Pierce said the protest was resolved at 6pm.
Prisoners were securely contained throughout, there was no risk to public safety and no-one was hurt.
Other parts of the prison were unaffected by the power outage, which happens from "time to time", he said.
Mr Pierce confirmed it was the first such protest of its type at the facility, and it was standard practice to lock down a facility and keep prisoners in their cells during such an incident.
The incident would be investigated and prisoners involved were likely to face an internal misconduct hearing and possibly disciplinary action.
The Otago Corrections Facility accommodates up to 485 low to high-medium security men.
