A net 43 per cent of retailers are optimistic, up from a net 29 per cent in March, as are a net 46 per cent of service sector firms, up from 38 per cent last time.
Retailers' expectations of their own activity are at a 23-month high and profit expectations the highest for 11 years.
But confidence in the agriculture and manufacturing sectors slipped, by four and six points respectively, while construction dropped to a net 38 per cent optimistic from a sky-high net 61 per cent in the previous survey.
"It appears we are moving in the right directions, growth-wise," the bank's chief economist, Cameron Bagrie, said.
"But we need the right mix of growth if it is to prove sustainable."
The survey suggested a broadening in momentum beyond housing into the domestic economy.
"Time will tell whether this is realised," Bagrie said. "Auckland has become a housing focal point and is the obvious candidate to test the flow-through into the broader economy.
"The regional results do not show it yet - the Auckland survey results do not stand out from the rest of the regions."
The workhorses of the economy such as agriculture were not kicking on, and faced a persistently high currency despite falling commodity prices, he said.
"This is not the stuff of which export-led recoveries are made."
The domestic economy could carry the baton for a circuit, but it would run out of steam unless the income-generating sectors took over.
Firms' investment intentions lifted three points to a net 18 per cent positive, the highest reading since 2005 and well above the historical average of a net 12 positive.
Export intentions improved for the fourth month in a row, rising two points to a net 23.
But this indicator is still well below its historical average of a net 32 per cent positive.
Employment intentions bucked the trend and declined three points to a net 8 per cent positive.
A net 19 per cent of firms expect to raise prices over the next three months, down three points on March.
Inflation expectations were unchanged at 2.8 per cent.
Bagrie said: "There is nothing in these results to waken the Reserve Bank from an extended siesta of an unchanged official cash rate."