The Auckland Dragon Boat association had to cancel its practise sessions after safety warnings of 'hazardous substances' were reported for their training area.
The Auckland Council's Safeswim website issued a safety warning for St Marys Bay, after water runoff from the Sky City convention centre was released into the harbour.
A club member, who didn't want to be named, said she didn't feel safe to go into the water.
"During training, we get completely soaked...there's no way to stay dry on those boats."
"It's frustrating because we have a competition coming up in Hamilton that we're trying to train for, and we've had two nights where we can't train, and we can't go in the water."
The member had just joined this month when the season opened, and was attending training two nights per week.
She is keen to get back out on the water, but wants reassurance they can complete their training 'without being poisoned'.
One of the teams - the Pink Dragons - is a collective of breast cancer survivors. The club member stressed that these women are still in a fragile condition of health, and they use dragon boating as a physical way to recover.
"The last thing these women need is to be exposed to hazardous levels of toxic chemicals which were deliberately dumped there.
"It makes me really angry that they're putting people's health at risk when they could take it elsewhere."
Association chair Bill Lomas said they have between 140-240 people on the water most evenings and Sunday mornings, but they didn't want to take the risk.
"We take the water quality and the safety of our people quite seriously, so we were in contact with the council and Safeswim from about 9am yesterday morning to try and find out whether we could paddle in the water and what would happen.
"In our effort to be conscious of people touching the water and [all the chemicals] that are present on a construction site, it's safe to say we'll be closed for the next few days."
Lomas said it was a shame to cancel the sessions, but they had no other option.
"We have 20 people to a boat. You're hands are in the water, you're getting splashed by everything else that's coming up. So it does come into contact with your face, with your skin, your eyes, and that's just what dragon boating is."
Lomas said several trainings each year are cancelled because of water quality issues.
"It's quite often that St Marys Bay is a 'not-safe-to-swim' area...it's been this way for ten years."
Safeswim programme manager Nick Vigar confirmed that water contaminated with 'sufficiently low' hydro-carbon levels was pumped into the sea for the first twenty hours from the start of the fire.
He said the water had been redirected to the wastewater treatment plant in Mangere from 6.30pm last night, and they were expecting a toxicology report on the water quality next week.
In the meantime, Vigar advises the public to treat water as potentially hazardous.