The $218 million prison attracted criticism when it opened in 2007 for its underfloor heating and each wing having a flat-screen television, with each prisoner also allowed his own television set in his cell, subject to approval.
Mr Pierce said the protest was resolved at 6pm, with prisoners securely contained throughout, no-risk to public safety and no-one 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 with prisoners involved likely to face an internal misconduct hearing, possibly resulting in disciplinary action.
The Otago Corrections Facility accommodates up to 485 low to high-medium security men.