An official drought already declared for Northland could spread to much of the upper North Island by Christmas.
Federated Farmers and Ministry of Agriculture representatives met this week to determine whether a wider drought should be declared. December 22 was set as decision day.
Parts of Auckland and Northland have had the driest spring since records began more than 50 years ago. Both regions have already had water shortages.
Federated Farmers Auckland president Wendy Clark said she was confident a drought for Auckland, Waikato, Taupo, Rotorua and the Coromandel would be called.
"We're used to having a fairly harsh summer but this has come two months ahead of time," Clark said.
The situation on her Patumahoe farm had rapidly deteriorated in the past week. She was culling cows early and bringing in more feed to carry them through the next few months.
"Northland is ahead of us as it struck them first. They declared a mid-level drought last week."
It was the third time in the past 45 years they experienced drought conditions so early.
Some residents in the West Auckland community of Karekare were already having to truck in water to fill their tanks.
In Northland, Kaikohe's Parihaka marae has closed because of water shortages. Interim chairman William Reihana said the situation had worsened in the past two weeks. "We're trying to make sure we have at least a bit of water. But it's going to be pretty tough."
Weatherwatch.co.nz head weather analyst Philip Duncan had little hope for farmers. He predicted some rain in coming days "but not enough to change things for the better".