The migration boom is continuing with the second-highest monthly figure in more than a decade, putting more pressure on interest rates.
Statistics released today show 4000 more people arriving than leaving long-term in May, the second-highest monthly figure since 2003.
The strong migration figures will add pressure for official interest rates to rise again in July, and may see rates rise further and faster over time, economists said.
Far fewer New Zealanders are leaving for Australia and more are returning from across the Tasman.
In the May year, the net loss to Australia was fewer than 10,000 people, less than a third of the loss in the previous year, accounting for the lion's share of the change in migration flows, Statistics New Zealand figures show.
Fewer people are leaving for Australia as the economy there cools and the job market prospects improve in New Zealand, especially as a result of the Canterbury earthquake rebuild.
The monthly net gain was down slightly on the 4100 seen in April, the highest monthly figure since 2003.
For the 12 months to May, the net migration gain was 36,400 migrants, the highest annual gain since the November 2003 year (36,700), Statistics NZ said.
Deutsche Bank chief economist Darren Gibbs said that if the rate of net migration in the past three months continued for a year, the annual gain would hit about 48,000, equal to a population gain of 1.1 per cent.
The past exodus to Australia was not expected to return until the Australian job market found a "firmer footing" Gibbs said, and that could be some time off.
The Reserve Bank warned in its June monetary policy statement that if migration was stronger than expected then interest rates could rise further and faster than forecast, perhaps adding another 50 basis points to rate rises over time, Deutsche Bank said.
Westpac senior economist Felix Delbruck said migration remained "extremely strong".
And with a substantial improvement in the Australian job market still looking some way off, Westpac said New Zealand was well on track to see annual net migration top 40,000 by the end of the year.
The latest migration figures were probably stronger than the Reserve Bank was expecting in its June statement he said.
Along with strong consumer confidence and strong GDP growth, the migration figures were another tick in the box for official interest rates to rise again in July, Westpac said.
Strong migration tended to support demand for housing, but so far there have been few signs the migration boom was reigniting the property market so far.
Westpac believed interest rates were a stronger driver of the recent trend in housing than migrant flows.
The Reserve Bank has raised the official interest rate three times since March to 3.25 per cent and is widely expected to lift it again next month to 3.5 per cent, pushing up floating mortgage rates, which are now sitting about 6.5 per cent among the big banks.
The central bank also imposed limits on low-deposit loans late last year, knocking first-home buyers especially.
Meanwhile, today's Statistics NZ figures showed New Zealand recorded its highest net gain of migrants, 42,500, in the May 2003 year.
In the May 2014 year, there were 99,900 migrant arrivals (up 14 per cent from 2013), and 63,500 migrant departures (down 22 per cent).
The seasonally adjusted net loss of 200 migrants to Australia in May 2014 matched the loss recorded in April 2014. These were the lowest monthly losses since the series began in 1996. In the latest year, New Zealand had a net loss of 9700 migrants to Australia, down from 32,900 a year earlier.
Net gains were recorded from most other countries, led by India (6600), China (6,300), and the United Kingdom (5700).
The net migration gain has been positive and mostly increasing since September 2012.
Comparing May 2014 with May 2012, there were far fewer New Zealanders leaving for Australia (down 2000) . More foreigners were also arriving here, up 1300. As well, more New Zealanders are returning from Australia, up 600.