Compulsory water rationing has been introduced for some farms on a section of the Taieri River in parched Otago.
Otago Regional Council has issued a water shortage direction for three farms that take water for irrigation from Paerau to Waipiata.
Chief executive Peter Bodeker said the council had to issue the direction, and possibly others in the coming weeks, to secure the long-term viability of the river for all users.
Mr Bodeker said most of the other farms along the river are rationing their water take voluntarily.
He said the council wanted to ensure that minimum flows at Waipiata and Tiroiti are sustained.
He said any water available after the ecology of the river is preserved will be carefully managed. Council staff are keeping an hourly watch on flows.
The direction took effect at 8am today.