Environment Canterbury has issued warnings on four Canterbury rivers after potentially toxic algae was discovered.

They include the Selwyn River at Glentunnel Camping Ground, Waihao River at Gum Tree Flat Road (Don’s Hole), Waihao River at Bradshaw Bridge, and Saltwater Creek, (Ōtipua), Timaru near the State Highway 1 bridge.

Environment Canterbury said there are also other access points along the Selwyn and Waihao Rivers that may have benthic cyanobacteria present.

People are advised to treat every low-flowing river cautiously, check for the presence of benthic cyanobacteria and avoid contact.

People should avoid these waterways. Animals, particularly dogs, should not be allowed near the water until the health warning has been lifted.