Strict water controls are being introduced in parts of Otago due to continuing dry weather.
The Otago Regional Council says it will also be encouraging irrigators to manage what water is still available.
The council's resource management director, Selva Selvarajah, says it has been dry since November and that has put river catchments at, or below, their minimum flow levels.
The Shag River is below its minimum flow and Dr Selvarajah says the Kakanui River has also reached very low levels. The Waianakarua and Taieri rivers are also affected.
The council says staff will be on the lookout for any illegal irrigation.