"Higher petrol prices may be playing a role here, by leaving less disposable income in consumers' pockets," Stephens said.
"In addition, people may have become more worried about the impact rising fixed-term mortgage rates and the Reserve Bank's recently announced lending restrictions will have on their ability to buy a house, or on the value of their house if they own one. We noted a particularly big drop in willingness to spend on big-ticket items in Auckland."
Westpac economist Felix Delbruck said there was a clear split between urban and rural areas in the latest survey, with confidence falling in the main centres but rising in rural areas.
"We think this supports the idea that concerns around housing, most relevant in Auckland, have played a role in the latest dip in confidence," he said.
"Rural confidence will also have been boosted by the end of the recent drought and the big lift in the coming season's forecast dairy payout."
Consumer confidence fell among all income groups, but particularly among those on lower incomes, Delbruck said.