Almost 50 firefighters are continuing to battle a blaze near Tikokino, in Hawke's Bay on Wednesday.
The large fire has been burning for nearly two days.
The blaze had been contained by firefighters, but flared up overnight due to dry conditions and strong winds.
Hawke's Bay residents are being urged to keep an eye out for danger as fire resources in the region are stretched.
"Hawke's Bay right now is under extreme conditions," said area manager Ken Cooper. "Fire and Emergency are responding to multiple incidents, so if we could just ask members of the public to be vigilant and if you see any signs of smoke to call 111 immediately."
The fire has now been contained once again but strong winds are making it difficult on the ground.
"Conditions are very arduous - very high temperatures with gusting winds, and under the conditions, the terrain is very difficult."
Five helicopters are also on the scene.
State Highway 50 Maraekakaho to Tikokino, between Kereru Road and Butler Road, will be closed until at least midday, NZTA said.