One economist believes the second successive month of falls in the number of consents for new houses and apartments is surprising, particularly in the accelerating Auckland housing market.
Official figures show the number of dwelling consents decreased a seasonally adjusted 3.8 percent, to 2108 in January.
Excluding volatile apartment numbers, permits issued fell 7.5 percent.
A senior economist at Westpac Michael Gordon said higher house prices, a rising population and stronger efforts by policymakers to stimulate house building should be prompting more consents.
Statistics New Zealand said the trend showed consents were rising and it was at its highest level since July 2007, if apartments were included.
The department said the trend was flat once apartments were excluded.