Economic activity grew 1.4 per cent in the September quarter to be 3.5 per cent larger than a year earlier, the strongest results for four and six years respectively.
But New Zealand is a grass-fed economy and that imparts volatility to its quarterly data. Agricultural activity surged 17 per cent in the September quarter, led by dairying but reinforced by sheep and beef.
When forestry (up 8.2 per cent) and fishing are added, primary production was up 13.9 per cent in the quarter and contributed the lion's share, 0.9 percentage points, of the quarter's overall 1.4 per cent growth.
But that followed two quarters in which it shrank as a result of last summer's drought.
For the year ended September, as a whole agriculture, forestry and fishing contracted by 3.7 per cent compared with the year before.
By contrast over the past year manufacturing grew 1.8 per cent on the year before, to the highest level in five years and 19.4 per cent above its trough in June 2009.
And construction activity, which fell 1 per cent in the September quarter reflecting a drop in heavy and civil engineering work and despite an 8.5 per cent increase in residential building, was up 13.8 per cent in the year ended September compared with the September 2012 year.
Overall, annual average economic growth was 2.6 per cent.
ANZ economist Mark Smith said Mother Nature had provided some quarterly volatility but ignoring that noise it was clear the economy had a good head of steam up.
"Indeed we can now see some upside risk to our expectation of 2 per cent growth in the second half of this year which as it stands would be more than twice the 0.8 per cent expansion in the first half."
On the spending side of the national accounts, household consumption was up 0.4 per cent, its weakest result for a year.
But overall domestic demand grew a strong 2.7 per cent in the quarter, driven by an 8.5 per cent rise in residential building investment and an 11.6 per cent rise in investment in plant, machinery and equipment.
Net exports, however, subtracted from growth, with import volumes rising and export volumes shrinking. Much of the surge in dairy production in particular went into inventories rather than crossing the wharf.
The quarterly rise of 1.4 per cent was stronger than the Reserve Bank or other forecasters - Westpac excepted - had picked. Together with upward revisions to growth in the March and June quarters it indicated stronger momentum in the economy this year than had been expected.
This would make the Reserve Bank more comfortable about raising interest rates, most likely in March, said Westpac economist Michael Gordon.
"However, we believe that recent developments - stronger than expected near-term growth, the US Federal Reserve's early tapering, and the reduced risk of rate cuts by the Australian central bank in the near future - could encourage the Reserve Bank to move faster than previously signalled," he said.
The Fed announced yesterday it would begin to taper its quantitative easing, that is, scale back its purchases of US government debt and mortgage-backed securities, but its forward guidance on its policy interest rate remained very dovish.
ASB economist Christina Leung said the Fed move had not dented the strength of the kiwi dollar as yet and its recent strength could persist.
She said it would also take time for the Reserve Bank to assess the impact of its loan-to-value ratio restrictions on mortgage lending.