The parched North Island won't see rain for at least a week as hot, dry weather continues in what has been described as one of the worst droughts since the 1940s.
Farmers say they are set to lose a third of their incomes and the $1 billion cost to the economy so far is rising every day.
The MetService says it will remain dry over most of the country this week but there is a chance of rain next weekend.
Forecaster Gerard Barrow said a low was forming in the Tasman Sea, but it was too early to know if it would track across the country.
Federated Farmers president Bruce Wills, a Hawkes Bay sheep and cattle farmer, said the cost to the economy was increasing by the day.
ANZ has estimated the cost to the economy at $1 billion, which could blow out in the coming months, Mr Wills said.
"There has not been a drought like this in Hawkes Bay since 1952."
Climate change expert Dr Jim Salinger said the North Island had not experienced a drought so severe for 70 years.
In the season to February 28, the North Island lost 362mm of moisture from the soil through evaporation - making it a far drier season than the 1945-46 season that recorded 361mm for the entire season from July 1945 to June 1946, Dr Salinger said.
Mr Wills agreed with Dr Salinger's assessment.
"It seems about right when you consider the worst drought in Hawkes Bay," he said.
"The drought in 2007 and 2009 was bad and the cost to the economy amounted to $2.8 billion."
Mr Wills said the drought was going to cost him about a third of his income.
Northland, Auckland, Waikato, Bay of Plenty and Hawkes Bay have been declared drought zones and farmers from Manawatu-Rangitikei, Wairarapa and Taranaki hope their areas will be declared soon so they can have access to government benefits.
Mr Wills said the South Island was in better shape because it was getting rain and "hopefully it will stay that way".
And Dr Salinger said that while the South Island was dry, he did not expect any of the regions would be declared drought-affected. "This is definitely a North Island event."
•Two people had to be treated for smoke inhalation as a scrub fire burned close to houses in the South Auckland suburb of Clendon Park.
The fire yesterday burned through 1400sq m of grass and scrub in the Pitt St Reserve and caused residents of three nearby streets - Bellville Drive, Eloise Place and Bill Phillip Place - to evacuate their homes.
Fire Service spokesman Jaron Phillips said the evacuations were because of the smoke. "There wasn't actually a risk of the fire, it was due to the large amount of smoke."
The black smoke could be seen from across the city and when the wind shifted from a northerly to an easterly, it sent it directly into the neighbouring streets.