The IronMaori half ironman swim leg at Pandora Pond in Napier was called off today.
The event proceeded as a duathlon.
Following the heavy rain in the past few days, the Hawke's Bay Regional Council water quality monitoring results confirmed that the pond wasn't suitable for swimming.
Samples collected on Thursday indicated high levels of contamination and that the faecal indicator bacteria exceeded the national guideline.
HBRC tested for both E. coli for freshwater and enterococci for saline water.
The Hawke's Bay District Health Board advised that recreational activities in the pond could lead to increased risk of illness.
"Pandora Pond is generally not suitable for swimming for three days after heavy rainfall; the Pond should be regarded as being unsuitable for recreational activities until 72 hours after rainfall stops."
A spokesperson from the Napier City Council said the council had put signs up around the pond advising people against swimming.
"We can't stop people going into the water, but we would advise against it," he said.
Even though the swim was to go ahead organisers for the IronMaori event said should any participant not want to swim, they could opt for a run/walk instead.
On a Facebook post, IronMaori organisers had initially said they understood "there are no sewerage spills to consider, that there have been recent big tides which support lots of cleaner water moving in from the coast on incoming tides; and that water clarity/colour in Pandora as at Friday 1.30pm is good."
"Should there be an adverse event weather event or otherwise before the event started, the decision would be reviewed early Saturday morning with any changes announced at 5am on social media."
Upon review, the swim leg was called off.