Fire and Emergency incident commander Des Irving said the fire was approximately 80 hectares in size and it could take days to extinguish.
"We have significant challenges with the weather. The wind is gusting and it will gust up to about 70 kilometres an hour today," Irving said.
"That's creating some issues for us"
Five helicopters and three ground crews are working to bring the fire under control on Friday.
They were reviewing the conditions to ensure it was safe for air support to continue, he said.
The fire was in a forestry block surrounded by farmland and there was no immediate threat to any structures or properties, Irving said.
People are urged to stay away from the area.
Fire and smoke may be visible from State Highways 1 and 7.
The wind was expected to reduce over the weekend, but there was no sign of rain in the forecast, Irving said.
He described it as a "long duration event", but he hoped it would be under control by Saturday afternoon.
"Once air operations are finished, there are trees still standing so we have to get in with our ground crews and extinguish the hotspots."
That included using specialist equipment to check that weren't any hotspots buried in the roots.
He encouraged people to check the forecast and the Fire and Emergency CheckItsAlright website https://www.checkitsalright.nz/ before lighting a fire.
"If you've had fires going and the forecast is for winds to increase ... check those fires and our preference is that you extinguish them."
It was currently "too dangerous" for a fire investigator to examine the area and work out the cause and origin of the fire, he said.
