The number of New Zealanders staying home or foreigners moving here has remained at near all-time highs.
Official figures show a seasonally adjusted net gain of 4270 in June, the second highest monthly gain since February 2003.
Departures for the year ended 30 June were down 22 percent, resulting in a net gain of 38,338 - the highest annual gain since the October 2003 year.
In the month of June, permanent arrivals from Australia matched the number of people leaving for Australia.
Westpac senior economist Felix Delbruck said fewer people moving to Australia explained the overall increase.
"A little bit on the stronger side of my expectations but it's a similar pace to what we saw over the last few months," Mr Delbruck said.
"Basically it's very strong. The big driver of this migration cycle has been movements across the Tasman by both New Zealanders and Australians, so in other words fewer New Zealanders leaving for Australia, more New Zealanders coming back and also more Australians moving to New Zealand.
"So it's really all about the weak Australian job market, the improving New Zealand job market and the fact that New Zealand is just now relatively speaking a slightly more attractive place to move to."
New Zealand recorded its highest-ever net gain of migrants - 42,500 - in the May 2003 year.