The last time economic confidence fell to similar levels in the region was in late 2010 - another drought year, Westpac said.
Economic confidence in Auckland lost some of its recent shine. Even so, Auckland remained the second most optimistic region in the country after Canterbury.
In Waikato, responsible for about 48 per cent of New Zealand's dairy production, the mood turned for the worse, with confidence falling to its lowest level since March, 2009. The region is now the second-most pessimistic in the country after Northland.
"Drought has clearly hit local [Waikato] dairy farmers hard, with rising global prices providing little in the way of immediate comfort." Westpac said in a commentary.
In the Bay of Plenty, confidence remained weak but had improved marginally over the past three months. The Bay of Plenty economy continued to face a range of other challenges, including the Psa blight, which has devastated kiwifruit farmers, high unemployment, and the high New Zealand dollar.
In Gisborne/Hawke's Bay, confidence plunged back into pessimism as dry weather hit farmers hard. Economic confidence is now the lowest since late 2008.
Three months ago, the Taranaki/Manawatu-Wanganui enjoyed one of the highest levels of economic optimism in the country. Drought has now eroded much of that lead, with only Waikato suffering a bigger decline in economic confidence, Westpac said.
Economic confidence in Wellington remained pessimistic, but has improved for the third time in a row. In the far south, Southlanders' economic confidence saw by far the biggest lift of any region, rising from deep pessimism back to cautious optimism. Southland has enjoyed good growing conditions and was benefiting from the surge in dairy prices.