Whanganui firefighters took part in the battle against a large fire at Hawera Intermediate School yesterday.
The blaze broke out before 6am in a two-storey, 10-classroom block. It was well involved by the time firefighters arrived, and the school suffered extensive damage.
The school was closed yesterday and will remain closed today.
Whanganui fire service senior station officer Craig Gardiner said crews were called in from Wanganui and New Plymouth to take over from the Hawera crews.
"These guys [the Hawera firefighters] are volunteers, and they had jobs and families to go to."