"To say we are extremely saddened and disappointed would be an understatement. It's quite heartbreaking - but it would be more heartbreaking if someone got Covid."
Skipworth said Covid had been "financially crippling" over the 2020-21 period, and said 3,300 people had signed up for the 2021 event.
"We went from nine events to one small and one big event. In 2021 we only managed to host two small events, and because of the financial impact we hope whanau transfer their entry to next year.
"However, a refund is possible."
She added that a fair few of the participants had already transferred to next year.
"A third of the participants had already transferred prior to our official announcement on October 26."
Skipworth said 2022 was going to be a big year for the event.
IronMāori was first held in 2009 based on Pandora Pond but the East Pier reserve and Ahuriri became its new home in 2019 due to ongoing swimmability concerns.
Skipworth was awarded the Queen's Service Medal in 2014 in recognition of her efforts in establishing the event as a major contributor to health and wellbeing.
For those signed up for the December event, Skipworth said an email had been sent to all registered participants with further details surrounding the decision and participants were advised to check spam folders. If you did not receive the email, please email info@ironmaori.co.nz.
In 2022 the Quarter & a Half event will be held on November 5.