People in the Wellington region are being warned to take care around parts of three rivers following the discovery of potentially toxic blue-green algae.
The algae has been found in the Hutt, Akatarawa and Mangaroa rivers during routine monitoring.
Wellington regional council says medium-risk warning signs have been posted in the affected areas of the waterways.
People can still swim or walk their dogs, but should keep an eye out for algal mats.
