Anna Kare, who was at the park when the boy fell but did not see the incident, said he was burned head to toe and screaming in agony as a teenager carried him to his parents.
She said witnesses began pouring cold water on his body and his family called 111.
"There was screaming and yelling - it was just horrible. He would say, 'My feet, my feet,' then after the water he was saying, 'My face, my face,' then back to his hands again."
Rotorua District Council parks and recreation manager Garry Page said all the pools at the park could reach 100C - boiling point - and were fenced off for that reason.
Inspections had been carried out after the incident and the council was satisfied that the park was safe.
"Signage was up," Mr Page said. "People are still using the park and as long as they stick outside the fences they will be fine."
The council could not do any more about the death until someone came forward with more information.
Rotorua's hot pools have claimed several victims over the years, most recently in August last year when a 61-year-old man was found dead in a privately owned pool.
- additional reporting: NZPA