"There's been a lot more demand. Some of the new entrants are last year's spectators, who watched people of all shapes and sizes and thought, 'if they can do it, I can do it'."
Now in its sixth year, the event aims to introduce Maori to physical exercise and activity while providing a family and group atmosphere.
The event was born in Hawke's Bay and has since spread to Australia's Gold Coast, where a triathlon event was held in July.
It isn't solely for Maori with people of all ethnicities, ages and fitness levels encouraged to participate.
Registrations have closed for this weekend's half IronMan event, which will involve a 2km swim, 90km cycle and 21.1km walk or run, although late registrations are still possible for kids interested in Friday's events.
The half IronMan is on Saturday at 6.15am and the Tamariki (children aged 7 to 12) and Rangatahi (children aged 13 to 17) events are on Friday at 9am and 11.30am respectively. All races start from Pandora Pond, Napier.
Children and teens could register for their events on Friday at Pandora Pond from 7am.