Parts of the South Island could soon be hit, they said, with farmers particularly vulnerable.
Agriculture, a prime driver of New Zealand's economy, has suffered losses estimated at $820 million, the BBC reported Friday.
"What we are telling our farmers is forget about this season, start concentrating on next season," said Derek Spratt, the chairman of New Zealand's Rural Support Trust.
A forecast of rain this weekend, the first in two months, could bring some relief, officials said.
The impact of the drought is visible from space, with satellites capturing images of large parts of New Zealand turned from lush green to parched brown.
Not everyone has reason to complain, though; New Zealand winemakers say the current sun-soaked conditions are perfect for their vineyards.