"Apartments tend to be really volatile month to month," said construction statistics manager Melissa McKenzie.
"October's figure is the lowest number we have seen since April 2016, although we know there are more apartments in the pipeline. We don't include dwellings in the consent statistics until the final stages of work are consented, when we get the highest value for the project."
Building consent statistics count the number of individual apartments consented, rather than the number of apartment buildings consented.
More than 75 per cent of apartments consented in the past year were in Auckland
A spokesman for Housing and Transport Minister Phil Twyford said under-building was of serious concern.
"A Ministry of Business, Innovation and Employment analysis of the rate of house building compared to the population shows several important things.
"The current house-building rate is still below the pre-global financial crisis norms and a quarter below the 2004 building boom. In Auckland, it's worse - only two-thirds of the 2004 boom," the spokesman said.
"If the build rate under National had kept pace with the previous build rate, there would be virtually no housing shortage: an extra 43,000 houses would have been built in Auckland against the shortage of 45,000, an extra 66,000 would have been built nationwide, against the shortage of 71,000," he said.
"This also shows that lifting the build rate is not implausible, we achieved the about the same build rate we need for KiwiBuild as recently as the early 2000s," he said.