Chaos broke out at Whanganui Prison on Wednesday night with a fire started and a number of windows smashed by inmates.
Corrections said it was investigating how the fire was able to be ignited within a cell and two of the inmates involved were removed from the prison.
The director at Whanganui Prison Reti Pearse, said at about 3am on Thursday a sprinkler on the landing was activated after prisoners managed to "ignite material" in their cells.
The smoke activated the wing sprinklers which immediately doused the fire and the Fire Service attended and reset the alarm and sprinkler system.
Earlier that same night prison staff responded to a series of banging noises in the wing and found prisonsers had broken windows in three cells.