Auckland Normal Intermediate School in Mt Eden became the scene of a frantic battle between flame and firefighters on Wednesday.
Photos show thick smoke rising from the school hall, choking the neighbourhood. Nearby houses were evacuated and emergency services rushed to battle the blaze.
The fire has now been contained. There have been no reports of injuries.
According to media reports, people have been working on the school's roof. It's not clear if they might have started the fire.
The school was due to reopen to students on Tuesday, January 29.