"District or regional groups need to make a formal request for any such a declaration and at this stage this hasn't been deemed necessary.
"This threshold would be reached when the lack of rainfall has an economic, environmental and social impact on farming businesses and the wider community."
Many in the agriculture sector are already facing irrigation restrictions as water levels drop. Farmers are de-stocking and using feed supplies, others have already dried off milking herds, and there are fears yields could be down 50 per cent.
In south Canterbury, the Opuha Lake has only enough water to support irrigation for about another month, and other schemes are operating on 50 per cent restrictions.
Mr Guy spoke to farmers during a visit to a farm owned by Federated Farmers board member Chris Allen.
He said farmers in the region were "hopeful" of rain soon, and reminded rural communities that support was available through Government agencies, including the Inland Revenue Department.
"I would urge farmers to make use of the good advice and support available from their local Rural Support Trusts. They are doing a great job of coordinating farming communities and providing information," Mr Guy said.
"Unfortunately droughts are nothing new for farmers. Two summers ago we suffered through the worst drought in 70 years, and last year we had severe dry spells in parts of Northland and Waikato.
"It is a tough situation for many with this coming on top of a lower dairy payout. However, I know that farmers are resilient and have come through many challenges like snowstorms, earthquakes and commodity price fluctuations before."
Federated Farmers national president William Rolleston said Canterbury farmers were used to dealing with long, hot summers, but this year the "big dry" had hit much early, and irrigation schemes were failing to keep pace.
Meanwhile, ANZ Bank announced an assistance package for farmers affected by the extreme dry conditions.
"The 'big dry' is affecting areas which haven't experienced extreme conditions like these for many years, so for a lot of farmers this is new territory," the bank's commercial and agricultural managing director, Graham Turley, said.
"We recognise the challenges and anxiety this is creating for farmers, which have been exacerbated by forecast low dairy payouts. We're offering targeted assistance, recognising that the situation may require more complex solutions for some.
"The impacts of serious weather events like this don't just affect the farmers and their local area but will be felt right through the economy."
He advised farmers to contact their local ANZ advisor for details on the assistance package, which includes suspending loan repayments, waiving fees and interest rate reductions on certain products, and providing access to discounted short-term funding.
- additional reporting Michelle Nelson, Ashburton Guardian
Main centres forecast
* Whangarei - Tomorrow will see morning cloud before turning fine, with a southeast breeze and a high of 26C. Thursday will see long fine spells, southeast breezes and a high of 26C.
* Auckland - Morning cloud, then fine with southerly breezes and a high of 25C. On Thursday it will be mainly fine with light winds, an easterly cloud in the Gulf, and a high of 27C.
* Hamilton - Tomorrow will be fine with southwesterly breezes and a high of 26C. Thursday is fine with light winds, and a high of 27C.
* Tauranga - Fine on Wednesday with light winds and afternoon sea breezes, and a high of 26C. Thursday will be fine with light winds and sea breezes, and a high of 25C.
* Wellington - A fresh southerly and showers developing in the morning, with the chance some may be heavy, a high of 19C. Fine on Thursday, with morning and evening cloud, the southerly dies out, and a high of 19C.
* Christchurch - A few showers on Wednesday, clearing in the evening, as southerlies develop, with a high of 18C. Thursday will see morning cloud, turning fine, with northeasterlies developing and a high of 22C.
* Dunedin - A few showers tomorrow, clearing in the afternoon with southerlies dying out, and a high of 15C. Morning cloud on Thursday, turning fine, with northeasterlies developing, and a high of 19C.
