Four helicopters were sent to fight a fire that closed State Highway 1 north of Kaikōura.
Fire crews were called to the blaze on the hillside about 5km north of the Kekerengu Store on SH1 at about 1.55am on Wednesday.
It started from a controlled burn that flared up overnight due to high winds, a Fire and Emergency NZ spokesman said.
The fire is thought to have reached a size of about 20 hectares.
SH1 between Clarence and Wharanui at the Tirohanga Stream Bridge was closed to traffic but fully reopened at about 10.40am.
He said they have spoken to the Department of Conservation as some of the fire has burnt through land they own.
A KiwRail spokesperson said the Main North Line between Kekerengu and Wharanui is closed.
"There is currently no impact to our scheduled train services."
A resident says the fire is huge after being blown all night by 'dynamic' winds.
The women has only just managed to get through the road closure for her job at the Kekerengu Store.
The FENZ spokesman said four helicopters were sent to the scene at first light.
Strong winds and the fire being on steep country terrain is making it difficult to contain, he said.
OPINION: They need to rip, sh*t and bust. Slash unnecessary spending.