"There are big deep gullies and a lot of hot area in there. It spread very rapidly.''
The fire is now under control and the helicopters have been stood down.
Fire crews are currently working on putting out little spot fires caused by embers.
He said firefighters were fine for water supply, despite initial fears they would run short.
Fire crews would spend the rest of the day and overnight keeping an eye on hot spots.
Earlier story:
Fire Service northern communications shift manager Steve Smith said there was a large scrub fire on Taupo's County Ave.
He said the fire was endangering buildings near the park, thought to be Spa Thermal Park, and a water tanker was on its way to assist the Taupo Fire Service.
Mr Smith said they received a call about the fire at 2.23pm.
Daily Post reporter Laurilee McMichael, who is at the scene, said there were five fire appliances and two helicopters fighting the blaze with monsoon buckets.
The monsoon buckets are being filled using a hose attached to a fire truck as well as a fire hydrant.
She said it appeared the fire was behind the Taupo mobile shop stall site. She said there was a lot of smoke and flames could be seen.
Emergency services had closed the road at the intersection of AC Baths Ave and Country Ave.
Witnesses said there was more than one fire and that the wind was picking up causing the fire to grow.
A group of five teenagers who had been swimming at the AC Baths went across the road to where the fire was to take a closer look.
They described it as being as big as two rugby fields, if not bigger.
They said they could hear the fire crackling in the trees.
"As the pine needles fell to the ground, they would start little fires on the ground,'' one of the teenagers said.
The teenagers told The Daily Post they were running around trying to stomp out the fires.
They said the fire would spread quickly from one tree to the next.
The teenagers were later told to leave the area by emergency services staff.
Mrs McMichael said there was a large crowd of onlookers gathering at the scene. She said there were no houses in the immediate area of the fire but there was a camp ground a couple of hundred metres away. So far, that had not been evacuated.
"The police are keeping a really close eye on everything.''