A potentially toxic algae has been found at the Tukituki River at Red Bridge (Waimarama Road) and Tennant Road.
The algae was found this week after the river receded in dry weather exposing the algae on the river bed edges.
Hawke's Bay Regional Council is warning people to be wary as the algae may be toxic.
People are advised not to swim and dog walkers are advised to take extra care to keep their pets under control when walking them in the river bed.
Hawke's Bay DHB staff have posted warning signs at the affected locations.
