A firefighter has been taken to hospital for "precautionary reasons only", following a large blaze at a Hokitika high school, a spokesman said.
Police are warning the public to stay away from the immediate area as the smoke is toxic.
Tasman District Acting Senior Sergeant Malcolm York said people needed to move away from the site as large plumes of smoke are said to be toxic.
A firefighter has already been taken to hospital, for what was said to be "precautionary reasons", a Fire Service spokesman said.
Mr York could not reveal any other details about what may be burning inside the two-storey administration block. The roof of the school's hall is also ablaze.
A police statement released this afternoon said: "Local residents who are experiencing smoke entering their properties are requested to move away from the smoke.''
Fire crews are still battling the large blaze at a high school in Hokitika.
Seven crews are now at the scene at Westland High School, on Hampden Street.
Authorities were called to the school just before 1pm.
A two-storey building understood to be the administration block was on fire and had reached a second alarm intensity. It is now a third alarm blaze.
Mr Dunn said the fire had spread to the roof of the school's hall nearby, but that officers had managed to stop it from spreading to other buildings.
A two-storey building understood to be the school's administration block is on fire.
Authorities were called to the blaze shortly before 1pm.
A spokesman for the southern fire communications centre, Brent Dunn, said they received a call from someone who was at the school grounds at the time.
Mr Dunn said the building's roof was well-ablaze and that it had reached a second-alarm level.
The circumstances of the fire are not yet known.