Annual net migration has risen to its highest level in more than a decade, thanks to the faster-growing economy.
Official figures show there has been a net gain of 36,400 permanent and long-term migrants for the year to May.
The expanding economy has meant fewer people departing to Australia, while also attracting foreigners and ex-pats, mainly to Auckland and Christchurch.
ANZ Bank senior economist Mark Smith said that trend showed no sign of abating.
"The numbers are very high, around 4000 per month, so if you annualise that, that's around 48,000 people, which is the average we've seen over the last three months," he said.
Australia's cooling economy was a factor in the trend, with unemployment rates expected to continue falling in New Zealand.
"Australia's is likely to hold up where it is so, if you like, the relative attractiveness is more tilted in favour of New Zealand, and we are seeing the flows to Australia sharply curtail over the last year or so," Mr Smith said.
"This is likely to continue over the next six to 12 months."
Rate rise expected
ANZ believed the Reserve Bank would increase the Official Cash Rate again next month, which would lead to further interest rate rises.
"While migration is definitely a positive for expanding the supply side of the capacity, at the margin it probably adds a bit more to the demand side," Mr Smith said.
Meanwhile, visitor arrivals hit a record high of 161,400 for a May month, partly due to more holidaymakers from the United States and Japan.
On an annual basis, visitors numbers rose 6 percent to 2.8 million.
Despite the high New Zealand dollar, some improving economies were encouraging people to travel, Mr Smith said.
"The exchange rate is normally a major determinate of visitor spending but for the moment visitor spending appears to be holding up quite well," he said.
As well, initiatives such as increased direct flights to New Zealand from the faster-growing Asian economies were bearing fruit.