"It is awesome to finally have it up and open to the public for summer," she said.
Staff member Aurelie Kersaudy said the slide had been busy.
"There has been a consistent flow," Ms Kersaudy said, talking about the children not the water.
"They're good kids and well behaved," she said.
Slider 12-year-old Lucas Dynes said the GetWet MegaSlide was "a lot of fun".
"It's when you get to the top it's nerve-wrecking," Lucas said.
"Then it's really cool and exciting."
Rachel Clare, who had brought her daughter Daniella to the slide, said the attraction looked impressive.
"It's really fun and slippery and bouncy," said Daniella.
The Megaslide was Australian certified and approved by New Zealand's Registered Chartered Engineers, said Ms O'Leary.
It is in Blake Park, Mount Maunganui, near the skate ramp.
The GetWet MegaSlide costs $12 for half an hour, or $15 for an hour, and will be open Monday to Sunday 10am to 7pm, until the end of March.
Sliders must be at least 4-years-old and no shorter than 1.2 metres.