A fire in a classroom at Crawshaw School in Nawton is being treated as suspicious.
Pukete station officer Shane Thomas said the fire was out on arrival, but appeared to be arson.
The door of the classroom had been set on fire and a hole around the door was visible.
The fire was caught just in time, he said.
Children were at the school when fire trucks from Hamilton central and Pukete stations arrived.
There was a lot of smoke and the fire service used a ventilator to clear the block.
A neighbour across the road from the school called 111.
Crawshaw School principal Jillian Littlewood said the fire was out shortly before 8pm.
"Luckily it was very small - and it's out now," she told the Herald.
Littlewood said fire services were still investigating how the fire had started.
Two fire appliances were at the scene.