Police are looking into the possibility a fire at a Hamilton college was started by fireworks.
Two science classrooms were gutted by the blaze at Sacred Heart College late on Friday night.
Police are treating it as suspicious and are inspecting the wreckage on Saturday.
"There have been reports of fireworks going off near the school," said Acting Detective Sergeant Ian Foster.
He asked anyone with information to contact police.
"The fire caused extensive damage to the building which is not only a terrible blow for the students and teachers, but it will result in a substantial financial loss to the school," Det Sgt Foster said.