A suspicious fire at Kaiapoi North School has prompted police to call on the public for information.
The incident was reported at 1.45am on Thursday and the fire was well involved when emergency services arrived.
When staff arrived for work they were greeted to the damage which left some in tears.
No one was injured, but there was significant damage to the building.
Police would like speak to the man pictured, who they believed could assist with their inquiries.
If anyone knows who he is they can contact Detective Belinda Campbell at Rangiora Police Station on 0211911478.
A police guard was on the scene and a fire investigator would be there this morning to look at possible causes.
The destroyed classrooms were part of the Year 3 and 4 Paneke classroom block.
Principal Jason Miles said about 50 students had lost their classrooms.
He was alerted to the "horrible news" at about 2am.
Teachers and some students were in tears when they turned up to the school, he said.
All the year's work, resources and anything left in overnight were completely gone.