Varco said there was "no immediate danger" and it was in control but would burn for a long time.
It was a good reminder to get advice from FENZ before lighting a burnoff if unsure, he said.
Investigations into a suspicious house fire north of Nuhaka on Friday night are ongoing, police say.
Emergency services were called to the unoccupied house a few kilometres north of Nuhaka about 7pm on Friday, a Fire and Emergency New Zealand spokeswoman said.
The badly damaged house was believed to be unoccupied, with no reports of injuries or persons involved, she said.
A police spokesperson confirmed the fire was being treated as suspicious with investigators from FENZ and police conducting a scene investigation on Saturday morning.
Meanwhile, emergency services were called to Napier Port about 2.15pm on Sunday after a collision involving a forklift and another vehicle on Breakwater Rd, a police spokesperson said.
It was not yet clear if WorkSafe had been notified of the incident, she said.
A St John spokesperson said one person had been transported to Hawke's Bay Hospital in moderate condition.
On Friday, a Dannevirke Volunteer Fire Brigade crew had to remove one person with moderate injuries from a vehicle after a two-car crash on State Highway 2, in Dannevirke.
The crash was reported just after 5.30pm. The road was reopened by 7pm.
Emergency services also attended a crash on Tamumu Rd, in Waipawa.
Two people, one with moderate injuries, another with minor injuries, were taken to Hawke's Bay Hospital by St John ambulance.
One person was also taken to Hawke's Bay Hospital with moderate injuries after a single-car crash on SH51, near Awatoto, on Saturday about 9.40pm.
Several vehicles were also damaged in a nose-to-tail incident involving six vehicles on the Hawke's Bay Expressway between Napier and Hastings about 4.30pm on Friday.
