The Tarawera Ultramarathon scheduled to be held in two weeks has been cancelled, as has the New Zealand Motocross Championships.
It follows the country moving into the red Covid-19 Protection Framework following the Omicron community outbreak.
Ironman Oceania regional director Amy MacCormack said she and the team were disappointed the ultramarathon event couldn't take place.
She said they worked hard to find options to make the event work under the red setting on the scheduled date of February 12.
"However, due to the size, scale and nature of the event, along with the limited time, the only feasible and socially responsible option is to cancel the event," she said.
"This was an incredibly hard decision for our team to make, but ultimately the safety and health of our runners, support crews, staff, volunteers and the local community in Rotorua and Kawerau are our number one priority."
She thanked all those involved for their continued support of the event, which would return in February next year.
All registered athletes for the 2022 Tarawera Ultramarathon will be contacted by event organisers about options regarding their entry.
Motorcycling New Zealand announced today this year's New Zealand Motocross Championships would also not go ahead due to the pandemic.
Rotorua, Balclutha and Napier had been scheduled as host venues for the series' three rounds this year.
Monday's decision to call the championships off followed the cancellation of other motocross events that would usually provide pre-nationals build-up.
Motorcycling New Zealand said in a statement that its representatives held lengthy conversations with many parties involved in this series.
It said while difficulties were being experienced and spoken of by all parties leading up to the proposed event dates, the shift to red and the extra regulations that come with this, made many areas of delivery for these events untenable.
Motorcycling New Zealand general manager Mike Kerrisk said it was an unfortunate decision to have to make.
"To have the necessary manpower on the ground to keep groups of people distanced and compliant is virtually impossible. The host clubs were also uncertain about how they could operate with certainty and, considering all those factors, the financial loss to our organisation would have been significant."
He said the pandemic and restrictions had impacted sponsors and the level of support they could provide.