UPDATED 6.09pm: Fire crews have contained a fire at Westland High School in Hokitika, but the fire has already severely damaged parts of the school.

Seven fire crews were called to the school on Hampden Street, the first shortly before one o'clock this afternoon.

Large amounts of smoke were seen pouring out of a two-storey building, understood to be the school's administration block.

Police are asking the public to stay away from the school and large plumes of smoke being created by the fire.

Acting Senior Sergeant Malcolm York says the smoke is toxic, and people need to move away from it as much as possible.

He says people standing around near the school near the fire should also move away.

The cause of the fire is still unknown.

Westland District Councillor Andy Thompson is at the scene and says the blaze seems to have died down, but a helicopter is still coming in regularly to dump water on the fire.

He says workmen caused a small fire at the school on Wednesday, but now he says it seems they may have set it off well and truly.

Westland School Principal, Trevor Jones says there's extensive damage.

The school is closed until further notice.