Six helicopters were due to take off early this morning to monitor a large scrub fire that has been burning north of Twizel in the South Island overnight.

A Fire and Emergency NZ (FENZ) spokesperson said the helicopters would assess the conditions and how big the fire was.

They were hoping to have a plan of action by 6.30am.

Eleven trucks were called to the blaze that broke out at a quarter to eight last night, at Pukaki Downs.

But it remains too dangerous to tackle due to strong winds.

MetService has an orange strong wind warning in place for the Canterbury High Country until 10pm tonight, with severe gale northwesterlies and damaging gusts of up to 140km/h forecast in exposed places, particularly this afternoon and evening.

State Highway 80 is closed at the intersection with SH8 due to the blaze.

Waka Kotahi said no detour was available and asked people to avoid the area and to delay their journeys if possible.

Six properties on Mount Cook Road were evacuated as a precaution.

A man living close to Twizel fears the massive scrub fire near the town will spread fast in the strong winds.

Jason Swain, who lives about 15 kilometres away from the fire, said similar wind fanned the Ohāu blaze which destroyed 48 homes three years ago.

"That's probably the big worry, there's huge winds and we seem to be in the middle of the wind at the moment and that really pushed the fires around last time," he said.

"There's a lot of pine trees up there to burn, so I think it'll get bigger."