Six fires have been caused by patients at Tauranga Hospital's mental health unit so far this year, with charges being laid against two people as a result.
Bay of Plenty District Health Board clinical director of Mental Health and Addiction Services Sue Mackersey said the fires caused localised damage but no one had been hurt.
All patient-generated fires are investigated by police and as a result of this, two charges were laid against patients this year.
Two fires were lit in the last month, following on from four other fires earlier this year.
The fires do not include an incident in May, which involved a patient barricading himself into a hospital bathroom and threatening to set fire to a pile of paper and aerosol cans. The incident sparked a full emergency services call-out.