Farmers across Otago are being asked to conserve water, with some rivers across the region dropping to their lowest levels on record.
Otago Regional Council data for October-December 2017 shows ''extremely dry'' weather conditions in Central Otago and part of South Otago, and ''moderately dry'' conditions for the rest of Otago.
ORC engineering, hazards and science director Gavin Palmer said some areas had particularly low rainfall and the present spell of dry weather, combined with little snow cap to augment river levels from snow melt last year, meant most Otago river levels were low compared to average levels for this time of the year.
The Taieri River and Kye Burn hit record low levels in December, he said.
''The Taieri River's Canadian Flat site level was the lowest since records began in 1982, and the Kye Burn was the lowest since records began five years ago.
''The Kakanui River was also much lower than normal at 57% less than its average flow.''
Dr Palmer said data collected this week showed the Lindis and Cardrona rivers were dry in some sections, and several other rivers were ''at or below'' their minimum low-flow level.
When rivers reached this level, the surrounding community and stakeholders agreed to control the amount of water taken from them, to maintain the health of the rivers.
North Otago farmers taking water from the Kakanui and Waianakarua rivers had instigated voluntary water rostering as the rivers approached the minimum flow level.
Dr Palmer said the council was contacting the community this week, reminding people to actively monitor their takes.
''We're reminding people who irrigate that some rivers are below minimum low-flow levels, and to be mindful of their water-use consents conditions and responsibilities, and conserve water where possible.''
He said aquifers monitored by the ORC were also very low during December, particularly in the Hawea Basin, Wakatipu Basin, Dunstan Flat in Central Otago, South Dunedin and West Lower Taieri.
However, they were higher than average in North Otago, East Taieri, Roxburgh and Ettrick.
Niwa says Otago's weather is likely to be warmer than average for the next three months.