Statistics New Zealand figures showed that for the year ending September, 87,200 people arrived on a permanent and long-term basis, up 600, or 1%, from a year earlier. At the same time, the figure of 70,200 permanent and long-term departures was down 12,100, or 15%.
As a result, net migration was 17,000 in the September year, up from 4400 a year earlier and the highest annual net migration total since the September 2004 year, Statistics New Zealand said.
ASB economist Jane Turner warned that the rise in net migration might only be temporary.
"As conditions improve across the Tasman it may be a matter of time before a recovering labour market in Australia provides a lift to permanent departures."
In the meantime, the increase in net migration continued to support growth in household formation and underpin housing demand, she said.
The current improvement in the housing market activity, and house prices, should encourage a lift in residential building activity and help construction activity lift off its current lows.
The long-term arrivals from Australia offset the fall in arrivals from the United Kingdom, Ms Turner said. The change in the mix was also likely to be a result of the global financial crisis, and the recession in New Zealand.
"The weaker labour market has attracted fewer migrants from abroad, although it has not put off Kiwis returning home from Australia."
Short-term arrivals increased 3.8% in the September month, and were up 9% on the same time last year.
Once again, the boost stemmed from the surge in Australian visitors looking to spend their "Rudd Cheques" (the cheques paid out to taxpayers by the Kevin Rudd-led Australian Government) on New Zealand ski slopes, Ms Turner said.
As the stimulus ended, the flow of Australian tourists was likely to ease.
