The rebuilding of Canterbury has driven a modest rise in economic activity, offsetting falls in both manufacturing and agriculture.
Gross domestic product, a broad measure of the health of the economy, expanded a slower than expected 0.2% in the three months to September.
GDP for the previous quarter was also halved from 0.6%, to 0.3%.
ASB chief economist Nick Tuffley says the the food processing and mining industries fared weaker than expected.
He says there was not as much flow on from earlier strong milk production as anticipated and the mining sector was quite weak as there was a substantial drop in oil and gas.