Part of Raphael House Rudolf Steiner School in the Hutt Valley has been destroyed by a fire which broke out last night.
More than 30 firefighters were needed to douse the blaze, with the school's location making access to the fire challenging.
"The issue with this particular school is that it has a long, steep driveway which makes it very difficult for appliances of the fire service size to get up there, so that caused difficulties, " says Lower Hutt Senior Station Officer Rob Sullivan.
The damaged area was the only part of the school that didn't have sprinklers or alarms operating.
"The building that was on fire was a woodworking block and the fire originally started in the storage area and extended through to the end of the building of the actual woodworking block and we managed to stop it at that point."
Investigators are back at the scene today.