Harmful bacteria has been detected in the Patea River affecting recreational swimming holes running through King Edward Park and Windsor Park.
Water contact may be harmful to humans and animals. Signage advising people of the risk has been erected at the river.
A Stratford District Council media release says the elevated bacteria levels are likely a result of the recent warm dry weather and are expected to drop back to usual safe levels naturally over time.
People are advised to contact council on 06 765 6099 or check the public notices section of the Stratford District Council website before they swim to see if warnings have been lifted.
For further information on bathing water quality visit www.stratford.govt.nz/council/services/environmental-health/bathing-water-quality.