A small blaze broke out at Wiri Women's Corrections Facility in South Auckland overnight.
Fire and Emergency New Zealand crews put out the fire, which started about 9.30pm.
Northern communications shift manager Colin Underdown said no one was believed to have been injured in the blaze.
The fire wasn't the first at the prison - emergency services were called to two small fires last Monday.
It was revealed the fires were set by two lovelorn prisoners who wanted to share a cell.