Two small fires lit by prisoners at the women's prison in Wiri, South Auckland, has prompted a police and Corrections Department investigation.
Police were called out after reports of two small fires at 7.45pm on Monday night at the Auckland Region Women's Corrections Facility and are now investigating.
Department of Corrections northern regional commissioner Jeanette Burns said two prisoners had lit small fires in their cells.
Three prisoners had been taken off site for medical assessment for suspected smoke inhalation.
"A full review will be undertaken and the prisoners who started the fires will be held to account for their actions."
Staff responded quickly and extinguished the fires, Burns said.
Fire and Emergency sent two fire trucks and conducted an investigation but did not extinguish any fire, a spokesman said.