Registrations for the upcoming 2012 Ironmaori sold out in less than eight minutes when they went on sale.
The 2130 spots were snapped up on Saturday before the link could be taken down.
It was a repeat of last year's sales when demand was much greater than anticipated and 1500 entries were sold. This year, organisers were planning for 1500 spots but the online demand was so strong 2130 were sold before the link was pulled - with still more people begging for entry.
"It could have been six minutes, going by the time," organiser Heather Skipworth said.
"Many people have begged and pleaded to get in but we just can't take any more. We have planned an event for 1500 and we've ended up with 2130."
Its popularity was pleasing but it would require some shuffling and re-organising of the events logistics to cater to the unexpected growth in participants.
It also bodes well for Ironmaori ambitions, which organisers say is about trying to create a movement and journey to better health, rather than just an annual event.
Maori health statistics were not great, and she said Ironmaori was a way of helping people take control of their lives.
"We're trying to change that, and make people aware that they can change that.
"It's the support and the friendship that they get, it's just the whole kaupapa of Ironmaori, it's kind of encapsulating for a lot of people," she said.