"All of the parents ran toward the back of the slide to find the kids.
"The kids were terrified as the whole thing was flipping backward."
She managed to reach her son and lifted him off the collapsed slide.
"It took me about 10 minutes for my tummy to settle as I felt rather sick."
She said the children were lucky not to sustain serious injuries.
Worksafe NZ is investigating the incident, and Hamilton Gardens' business development manager Malcolm Hazelton said he was aware of parents' concerns.
"This is also a real concern for us -- we don't want visitors to independently-run events held at the gardens being put at risk, and we take health and safety very seriously at our site, and for events held there.
"We're in discussions with Gourmet in the Gardens about what's occurred at their event and we'll be making it very clear what we expect when it comes to health and safety of garden visitors. We're going to find out what's happened here and ensure it doesn't occur again."