Total building work in place rose 1.4% in the September 2013 quarter with residential building rising more than 8% but non-residential construction falling 6.4%.
Westpac says it had forecast a 6% increase in total work, largely because it had expected a small rise in non-residential work.
The bank says the outcome is weaker than the recent trend in building consents and a catch-up in later quarters is likely.