A fire that may have been deliberately lit tonight destroyed an unoccupied old two-storey building at Craighead Diocesan School for girls in Timaru.
Timaru Fire Service senior station manager Garry Parker told NZPA arson was one option being considered.
He noted that a shed had been destroyed and another damaged in a fire at Craighead about the same time earlier this week.
Tonight's blaze raced through Salmon House, an early 1900s building that had once been occupied by boarders.
It was no longer in use and was some distance from the main buildings which were in no danger.
Mr Parker said the fire, reported about 7.45pm, was difficult to fight because it was down a long drive and getting water to the blaze was difficult.
Local firefighters and units from Temuka fought the blaze and the Geraldine volunteer brigade was brought in to cover Timaru.
The Anglican school is state integrated and caters for day pupils and boarders from years seven to 13.