The trends for the number of new houses, both including and excluding apartments, have both been rising over the past year, Cardno said.
Economists warned against reading too much into monthly figures and said numbers had improved lately.
Goldman Sachs' Philip Borkin said the April data were 7.2 per cent down on March yet March data had showed a 20 per cent surge on February.
"We suspect that the surge in March was in part due to changes to building regulations that recently came into force, and so the pull-back in April is natural," Borkin said.
The latest numbers were respectable because on a three-month basis, figures were up and showed the strongest run since July 2010, he said.
Christina Leung of ASB said April's fall followed the robust increase in the previous month and overall the underlying trend in residential building demand remained one of a recovery.
"Continued rebuilding activity in Canterbury is fairly encouraging, and should help to alleviate the housing supply constraints in the region," Leung said.
Mark Smith of ANZ said the introduction of the stricter building code may have also contributed to the drop.
The trend in residential work remains upwards and issuance will strengthen over the next few months, Smith predicted.
Darren Gibbs of Deutsche Bank said the strongest gains were in the Waikato, up 46 per cent annually, Auckland up 39 per cent and Canterbury up 42 per cent.
Statistics NZ continued to report only a small number of consents identified as related to earthquake reconstruction in Canterbury - just 17 new homes in April, Gibbs said.
However, it was worth noting that Fletcher EQR, which is managing the EQC's repair programme, reports that it is now paying out about $60 million a month to contractors repairing damaged homes, he said.
The Auckland Council says only about 2500 residences are being built annually when the city really needs about 13,000 residences.
RESIDENTIAL CONSENTS
New dwelling unit consents
* 2007: 25,964
* 2008: 25,124
* 2009: 14,870
* 2010: 15,772
* 2011: 14,138
* 2012: 14,899
[Source: Statistics NZ, year to April]