Potentially toxic algae in Lake Taupo has led to the cancellation of the swim leg at tomorrow's Ironman 70.3 event.
Instead the race will now consist of a 3km Run, 90km Bike and 21km Run.
After receiving reports from the public of algae blooms, Waikato Regional Council scientists collected a number of algae samples on Tuesday and again yesterday from five sites.
Testing overnight by NIWA scientists has confirmed the presence of potentially toxic algal species, including Phormidium, at areas within Five Mile Bay, Acacia Bay, the main lake front in Taupō, Whakaipo Bay and Kinloch Beach.