A net 67.3% of respondents in the monthly survey expected business conditions to improve over the next 12 months compared with a net 70.8% who expected an improvement in the prior survey. February's reading was the highest since March 1994.
Net confidence is defined as the percentage of optimists minus the percentage of pessimists.
"Confidence across all the major subsectors is now north of +50 -- that's a sign of a broad-based expansion, as opposed to an upswing dominated by a few pockets of the economy," ANZ's chief economist for New Zealand, Cameron Bagrie, said.
A net 58.2% of respondents expected their own business activity to improve in the coming year, down from 58.5% in February.