Rivers across Otago are very low for this time of year and if rain does not fall during the next few weeks, the region could be in for a very dry summer.
Irrigation restrictions are imminent and the Otago Regional Council is working with farmers and irrigation groups to ensure they have measures in place to deal with the dry conditions.
Consultant hydrologist Dave Stewart said it was very dry around the region, although coastal Otago had so far managed to "skate by" due to the occasional fall of rain.
"The rivers are quite low for this time of year.
It won't take much for irrigation restrictions," he said.
The region had experienced a dry spell since late October and the National Institute of Water and Atmospheric Research (Niwa) was predicting little rain in coming months.
"If Niwa predictions are right, there will not be enough rain to sustain good growth throughout summer," Mr Stewart said.
There was potential for some rainfall in the next week, especially in the headwaters of the region's lakes, but it was not expected to get as far east as Dunedin, he said.
"It remains to be seen whether it happens or not."
The saving grace for farmers had been the good growing season during spring, which allowed many to put away hay and silage, Mr Stewart said.
However, if the rain did not happen, farmers would need to start making decisions about destocking or ensuring they had enough supplementary feed to get through a dry summer, he said.
It was not unusual to be this dry in December and in previous years the region had been saved by regular rain storms during the summer.
Council environmental information and science director John Threlfall said most rivers were recording levels in their lowest 10% of flows for the month and heading towards their primary allocation limits and minimum flows.
However, he had seen drier conditions at this time of year.
"Everything is drying out. We've had some rain but it's been showery."
Compliance staff were checking river gauges every fortnight to ensure they were recording correctly, to give farmers accurate information on which to base their water use, he said.
"We're working with farmers as much as we can. It's a wait-and-see situation."
The situation could turn around quickly if rain arrived and unsettled weather was forecast until Christmas, he said.
Dunedin City Council water and waste services manager John Mackie said there was no cause for concern about council water supplies.
Reservoirs were at 85% capacity, but a watching brief would be kept during the holiday period, he said.
