Smith described the incident as horrific.
"My child just fell eight metres," she said. "I've been told there were some spinal injuries. Thank God she wasn't one of them."
Her daughter, 12-year-old Amelia Peck from Ashhurst, suffered a sprained knee and was treated at Wairarapa Hospital. She later returned on crutches to the A&P show which was being hosted by Solway Showgrounds.
Amelia, who was part-way up the climbing side, fell on to a tent beside the slide, then to the ground.
"I was probably the first one to land," she said. "I was in tears, my knee was real sore."
Masterton 14-year-old Caleb Larsen also had a lucky escape. He was about to get on to the slide when it started tipping.
"The whole thing caved in," he said. "There were eight people on that side, more people on top. They were all screaming. A mate of mine had his nose smashed, he was trying to save the little kids."
Riki Edwards, also of Masterton, said: "All these kids were falling to the ground, a couple of kids grabbed on to me, couple landed on me.
"One girl went flying over me, hit me on the head. There was one girl that couldn't walk, I had to help her up."
Last night, four of the six children had been discharged from hospital. One may be kept overnight for observation.
Police and WorkSafe NZ are investigating. The owner of the slide, who would only identify himself as Eric, refused to comment until he had spoken to WorkSafe.
Site manager Ally O'Neill said: "We are very concerned about the children and until the investigation has been completed we are unable to comment further."
About 5000 people were at the show. The slide was one of 16 rides at the event.
This month several people were injured at the Christchurch event of the Monster Slide summer tour, which was also held in Auckland yesterday.
It had to move venues over health and safety concerns but no accidents were reported.