An early morning blaze at the Maungawhau School in Mt Eden has damaged the school auditorium.
Some 60 firefighters and two aerial appliances battled the fire in the two-storey building at 2.30am on Thursday .
No-one was in the building at the time.
Maungawhau School principal Linley Bruce said the worst aspect of the fire is the loss of irreplaceable artworks gifted to the school by the community decades ago.
She said damage was limited to the school hall, and classes are continuing as usual.
Police and fire safety officers are to investigate the cause of the fire.