Two prison wardens are recovering from minor burns after rescuing an inmate who set the bedding in her cell alight.
An officer's hand was burnt and another's foot injured in the fire at Christchurch Women's Prison on Tuesday night.
Department of Corrections chief executive Ray Smith says there have been about 50 fires in prisons during the past year.
Mr Smith says inmates use lighters or matches to start fires, trigger smoke alarms, smoke drugs and make weapons. He says these problems should ease when smoking is banned in prisons from 1 July.
Eight cells remain sealed off at Christchurch Women's Prison on Wednesday due to smoke damage. The repair bill is not yet known.
