Organiser Jude Rivlin said the workshops had been hugely popular - probably, in part, because of the glorious weather.
"The kids would paint for a while, get too hot, then dive into the pool and cool off for a while before painting again."
The mural, which runs across one wall of the pool, depicts the district of Ruapehu with local Maori mythology with tui, the awa and the mountain, she said.
Mihinui would paint the outlines and the kids would spray paint in like colouring in the images, she said.
"The age range was from about 9 years old to a few adults. Everyone loved the painting - they all really got into it."
At 6pm, when the pool closed, a free sausage sizzle was held by Mihinui for all his budding artist helpers.