The country's economic performance has been underpinned by rampant building activity, record tourism, and strong inbound migration which has stoked consumer spending, while a recovery in global milk prices has eased concerns about the health of rural New Zealand.
Despite the confidence boost, pricing intentions barely shifted at a net 16.8 per cent from a net 14.9 per cent, which Bagrie said was low. Inflation expectations for the coming year were steady at 1.44 per cent.
The Reserve Bank is watching inflation expectations closely as he grapples with a strong currency keeping imported goods and services cheap, making it difficult for him to meet his price stability target. While he's able to look through the effects of the kiwi and cheap oil prices, he's concerned that those will feed into long-term inflaiton expectations leading to stagnant prices.
Across the five sub-sectors, service sector firms remained most optimistic, while agriculture moved to second place from least positive in August. Confidence improved across all of the sub-sectors, ANZ's Bagrie said.
Construction expectations were strong, with a net 41 per cent of respondents expecting more residential construction in the year ahead, up from a net 36.4 per cent in August, while a net 27.3 per cent were optimistic about the commercial construction sector's outlook, compared to 23.8 per cent a month earlier.
A net 13 per cent of respondents see an expansion in livestock investment, compared to a net 11.6 per cent expecting a contraction a month earlier.
Businesses thought it was easier to get credit in September, with a net 8.7 per cent finding it hard, from a net 14.3 per cent in August.
"We're watching this indicator closely as a) loan-to-value restrictions tighten; and b) credit growth outstrips deposit growth - an unsustainable mix," Bagrie said. "The former needs to slow and the latter lift to restore some balance. There will be consequences."
Interest rates were expected to fall by a net 28.9 per cent of respondents, from net 38.4 per cent in August.