Hawke's Bay Regional Council is warning dog owners to avoid letting their pets drink river water following the death of a dog at a popular swimming spot.
The dog was at Tukituki River's Horseshoe Bend and council environmental science staff are investigating.
Interim chief executive Liz Lambert said the death was due to a suspected case of cyanobacterial poisoning.
Ms Lambert said the death was a sad consequence of the warm summer weather when there was always a high likelihood of algal blooms.
She said dogs at rivers at this time of year should be kept under control and owners should take their own fresh water for them to drink.