People, and dogs, are being warned to stay out of a Dunedin lagoon where a toxic algae has been found.
Cyanobacteria, a blue-green algae, has been found in the Tomahawk Lagoon near Dunedin.
The Otago Regional Council put up signs at the lagoon today warning people of the risks from the bloom.
Cyanobacteria can produce toxins which are toxic to people and animals.
It can cause skin rashes, nausea, tummy upsets, and tingling and numbness around the mouth or finger tips.
The council was informed of the bloom by a citizen scientist working at the lagoon, and the Otago Regional Council took a sample yesterday.
The council said the lagoon discharged into a stream running out to the sea so beachgoers in the area also needed to take care.
The council said cyanobacteria occur naturally but can increase during summer months.