People are being warned to stay away from the Ashburton River after a potentially toxic algae was found.

Increased levels of the toxic algae, cyanobacteria, has triggered the warning.

People using the Ashburton River are advised the water quality isn't considered suitable for recreation and bathing due to the risk to their health.

Cyanobacteria has been found to contribute to eye, ear and skin irritation, as well as gastrointestinal symptoms such as as vomiting and diarrhoea.

Dog owners should also be aware of the risk to the health of their animals.