The migration boom is rolling on with a net gain of 34,400 in the April year, the strongest in more than a decade.
Based on present trends, economists expect the net gain to top 40,000 and possibly hit 45,000 by the end of this year.
Statistics New Zealand figures out today showed 4100 more people arrived than left New Zealand in April alone, the second-highest gain on record. The highest monthly net gain was 4700 in February 2003, when a flood of overseas students came to universities here.
Westpac economists said the monthly pace of net migration has risen. They had expected the figures to hold steady at already "very high levels".
If the net migration gain in the past three months continued through the year, the annual figure would top 46,000.
ANZ economists said the annual inflow was on track to hit a record 45,000, with the bulk of the net gains going to Auckland and Canterbury, but Otago, Wellington and Taranaki would also get a boost.
The latest monthly surprise was mainly because fewer New Zealanders were leaving for Australia, as well as more foreigners arriving here.
The exodus to Australia has dried up.
In April there was a seasonally adjusted net loss of just 200 people to Australia, the lowest figure for that series, which began in 1996.
Far fewer people are leaving for Australia as the economy across the ditch cools down after the end of the mining investment boom. New Zealand's prospects look relatively brighter.
Economists say that spreads the population growth around the country, rather than concentrating it in places like Auckland, as happened in the past.
A decade ago, the migration boom was a key factor driving up house prices, with average price gains peaking at more than 20 per cent in 2003.
The latest boom in migration is seen as a factor pushing demand for houses again.
However, the Reserve Bank has leaned heavily against overvalued house prices by imposing speed limits on low-deposit home loans. New rules came into force in October last year, which led to a slump in such sales in the past six months.
In addition, the central bank has started to lift official interest rates, with two rate rises this year and a third expected next month, which will also help cool demand for homes.
Annual price rises have come off their recent peaks.
"We think the surge in migration will support the housing market this year, but not enough to stop prices from slowing as mortgage rates continue to rise," Westpac economists said.
The OECD's latest economic outlook report out at the weekend showed New Zealand house prices were 70 per cent overvalued on its price-to-rent ratio, the biggest gap between rents and prices out of the 31 countries surveyed.
New Zealand narrowly beat Canada, which was 66 per cent overvalued and Norway (64 per cent).
Overall, net migration has been positive and mostly increasing since September 2012.
In the April 2014 year, migrant arrivals numbered 98,800 (up 13 per cent from 2013).
Migrant departures numbered 64,400 (down 22 per cent).
That meant a net gain of 34,400 migrants in the April year.
Statistics NZ said that the only time annual net migration was higher was in 2002 and 2003.
New Zealand recorded its highest net gain of 42,500 in the May 2003 year.
In the latest year, New Zealand had a net loss of 11,100 migrants to Australia, well down from 34,100 a year earlier.
Net gains were recorded from most other countries, led by India (6400), China (6200), and the United Kingdom (5900).