Police and fire investigators in Christchurch are working to determine if a spate of fires in the Riccarton road area are connected.
Tasman House, on Riccarton Road, was extensively damaged in the fire which started about 3am on Sunday.
It was followed by two other smaller fires in a skip bin and another at a nearby school.
Neither fire caused extensive damage.
Acting assistant area commander Steve Kennedy says fire safety officers are now waiting for an engineer to give the all clear before investigations in the Tasman House fire can continue.
He says the fire service and the police will be working together to determine if the fires are linked.