A riot squad was called to Ngawha prison in Northland on Sunday afternoon after a group of inmates staged a protest.
The Corrections Department says the prison was locked down for about an hour while the situation was brought under control.
Corrections says the unrest broke out at about 2pm, after 20 or so inmates in a single cell block began protesting at having to be locked in their cells.
Prison Services general manager Jeanette Burns says the prisoners lit several small rubbish fires, and damaged some cells.
She says a riot squad, known as the advanced control and restraint unit, was dispatched from Auckland to deal with the prisoners and the disorder was under control within an hour.
The group of prisoners will now be split up, either by being moved to a different unit within the prison, or relocated to another facility.
Ms Burns says an investigation will be carried out, and it is likely to lead to the prisoners involved facing internal disciplinary action and possibly criminal charges.
