Federated Farmers leaders say they are worried that dry conditions starting to develop around the country may signal a summer drought.
"In the Waikato, we're seeing low soil moisture levels that we don't normally expect to see until the end of January and after the winter we've had, that's not good at all," said the lobby group's Waikato provincial president Stew Wadey.
The Waikato regional drought committee will meet next week to discuss the situation, but Mr Wadey said that in the meantime he was warning farmers who were struggling, to lower their stocking rates.
"I myself am running fewer cows than last year to ensure I don't run out of feed," he said.
Many regions were also experiencing higher temperatures than normal: on Sunday, Hamilton recorded the highest temperature for November in 90 years: 28.1degC.
The National Institute of Water and Atmospheric Research yesterday released figures that show several warm-weather records were smashed last month, especially in the South Island, where temperatures were up to 3.5degC higher than the usual average.
The month's warmest day was recorded in Cromwell (32.3degC), which was the town's highest November temperature in more than 60 years.
Towns across the central North Island, including Taupo, New Plymouth, Wanganui, also broke records, and some farming areas have had no rain for more than four weeks: Wanganui and Dargaville had 10mm in November, and Taupo and Hamilton both received 16mm - all well below average.
The top of the North Island is bracing itself for a dry summer too, with many areas drier in Northland than this time last year, and Agriculture Minister David Carter said yesterday that he was considering declaring a drought in both Waikato and Northland.
"It's abnormally dry at this time of year... and there is no significant rain forecast," he said.
"I think we are going to have potentially quite serious drought issues over the next month or two.
"We may consider - in the not-too-distant future - declaring drought."
Farmers did not usually see such dry conditions until at least January, and climate records show the Southern Oscillation Index - which calculates the difference in atmospheric pressure between Tahiti and Darwin - has moved in ways similar to the summer of 2007-2008, when a severe La Nina drought cost the New Zealand economy $2.8 billion.
Mr Carter also urged farmers to make decisions on stocking rates sooner, rather than later.
"Those that make the hard calls early, are the ones that tend to get through the drought best," he said.
"It would be my strong advice to take early decisions and look at getting rid of any surplus stock."
The return of dry conditions showed New Zealand was already facing climate changes from global warming, such as intensification of rainfalls: "In many cases we're seeing annual rainfall figures being the same as normal but the rainfall occurrence are far larger, and in shorter periods of time," said Mr Carter.
"It is a clear demonstration of the effects of climate change."