Taupo Fire Brigade acting station officer Sean McAvinue said Taupo fire crews received the call at 12am and immediately set for the scene 50 minutes away expecting the worst.
"It was quite tricky to get her out because we were operating in the blind," he said.
Specialist rescue equipment was used to free the girl who was removed after firefighters managed to get the roof off the cab.
Two of the children, aged 5 and 7, along with the children's grandfather were discharged from Taupo Hospital yesterday after receiving moderate injuries.
The young girl, who was flown to the Hawke's Bay Hospital by helicopter with moderate injuries, was last night in a stable condition, recovering well, a Hawke's Bay District Health Board spokesperson said.
Yesterday mother of the children thanked emergency services and motorists who stopped to help at the time of the crash.
"We want to thank everyone who helped free dad and the children, and get them out of the truck - they did a wonderful job and we are very grateful," the children's mother said.
Rural fire crews contained the blaze before calling off their efforts until daylight; returning in the morning with monsoon buckets.