You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
The presence of the algae was confirmed yesterday and warning signs were put in place at the site.
Council spokesman Ryan Tippet advised humans and their dogs should keep out of the contaminated water, and avoid drinking or touching it.
"A general rule of thumb is that if the water is looking green, to stay out of it and avoid any contact with algal scum. If you have swum in water that is contaminated with toxic algae, rinse off with fresh water as soon as possible," he said.
"ORC encourages dog owners to familiarise themselves with toxic algae and know what to look for when exercising dogs in or around rivers and lakes."
Anyone who suspected they were experiencing a reaction due to contact with toxic algae should seek medical attention.