The event was organised by the Rotorua District Council and the Travelling Tuataras, with 40-50 volunteers running the various activities.
Having a special Children's Day was a good excuse to take a break from the "routine, boring stuff" and have fun as a family, Rotorua mum Natalie Swinburne said.
Miss Swinburne took along her two children, with 8-year-old Sarah saying she was a fan of the pine cone throwing and playing the musical instruments.
Another Rotorua mum, Robyn Hall, said she loved the idea of a Children's Day.
"[You make] a special effort to go out and do something," she said. "It's a bit of a reminder to do it more often."
While her 3-year-old daughter Makenna sat quietly making play dough birds, some impressive fort making was going on nearby.
"Some of them are very serious," said volunteer and self-described "hut co-ordinator" Julie Voss.
Tuakana Tuaine, 11, and his two cousins spent more than half an hour collecting sticks from the forest floor and building their fort. He said he had had a great day and loved being creative. He also liked playing with the bow and arrows.
Rotorua's Julia Charity said the event was just as much fun for the adults.
"You bang into people. It's social for the adults," she said. "What I love about this is it's just old-fashioned fun."
Ms Walker said Children's Day events had been running in Rotorua for about 15 years. "It's about celebrating our children."