The Kiwi exodus across the Tasman has hit a 32-year-high, swelled by people fleeing quake-ravaged Christchurch.
Statistics NZ figures show 3300 New Zealanders left for Australia last month, topping the record of 2900 set in 1979.
The number who fled Christchurch last month was 800 - up from 500 in May last year, said Government Statistician Geoff Bascand.
"Since the earthquake on February 22, the city has experienced 1300 more departures and 400 fewer arrivals than in the same period in 2010," he said.
The chief executive of the NZ Business Council for Sustainable Development, Peter Neilson, said the higher wages and living standards in Australia were always an attraction for Kiwis, and the earthquake gave them "added incentive" to move.
"Real wages after tax of middle income New Zealanders have been on the decline in the last year or so, so it is not surprising given that real wage growth is happening in Australia that you get a significant migration outflow," he said.
But Mr Neilson said he expected some people would return as jobs in Christchurch became available when the rebuilding programme "goes into full steam" within the next six months to a year.
"The long-term issue is if we don't pick up our living standards again so the incentive to go to Australia is less, then we've got a major problem."
That optimism was not shared by sociologist and immigration expert Paul Spoonley of Massey University who warned that the exodus was a "very dangerous sign" for New Zealand and its economy.
"Once these people have found a job and are settled in Australia, then the short answer is that they are unlikely to be coming back," he said.
"We are losing people who are in their prime working age and very often, they take their family and children along with them.
"So effectively, New Zealand is losing two generations of Kiwis at least."
Professor Spoonley said Australia was a popular choice because it was one of the few destinations that non-skilled Kiwis could migrate to outside of New Zealand.
"The people who are leaving can afford to go, in terms of getting employment and many of those left behind in Christchurch are locked in there because they haven't got any option."
The 2006 Census showed that about 390,000 people born in New Zealand were living in Australia.
Christchurch commercial cleaning contractor Daniel Yeoh said he had seen first-hand the exodus from Christchurch as his business cleans up after those who have fled the damaged city.
"Landlords are left with hundreds of properties abandoned by people who have left the city, and I have been cleaning a countless number of them since the quake," said Mr Yeoh.
Many Cantabrians were continuing to "pack up and go" and "just leaving properties in a hurry".
Nationally, on a seasonally adjusted basis, there was an overall net outflow of 400 people last month.
"Net migration has been negative since March, when departures from Christchurch jumped," Mr Bascand said.
In the year to last month, New Zealand's net migration gain was 4600 - down from 18,000 the previous year, and below the average annual net migration gain of 12,000 over the last 20 years.
"The decrease in net migration compared with 2010 was mainly due to an increase in departures to Australia," said Mr Bascand.
- Lincoln Tan
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SURVIVOR SEEKS NEW LIFE IN BRISBANE
After losing her brother and almost her own life in the Christchurch earthquakes, Amy Cooney is looking forward to a fresh start for her and her family in Australia.
Ms Cooney was working with her brother Jaime Gilbert, 22, in a central Christchurch bar when the building collapsed on them in the February 22 quake.
Mr Gilbert died while holding Ms Cooney's hand.
Though she was pulled from the rubble alive, the trauma has remained with her, and she wants to put it behind her by shifting to Brisbane with her partner and three children.
She visited there last week on holiday and was convinced it was the right place to make her new home.
"We'll be there within two months," Ms Cooney told the Herald.
"We just have to sell what we can, and get out of here. The urgency after [last week's big quakes] was quite apparent."
Her Christchurch home has quake damage, but she plans to worry about it "from over there".
The move was driven in large part by the need to give her young children stability. Having a brother and her partner's sister living in Brisbane made it a logical step.
People in Brisbane could also relate to natural disasters, having lived through the killer floods this year, Ms Cooney said.
In May, she told the Herald that her nerves were "at the end, and I'm vulnerable".
And yesterday she said that when last week's two big quakes hit, she did a "stage dive" down the hall to protect her children.
"If I'm too tired, things start aching. I have to just consider that my body isn't as able as it once was."
- Jarrod Booker
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UP AND AWAY
Net migration loss to Australia ( in May)
* 1978 - 2408
* 1979 - 2944
* 1980 - 1910
* 1990 - 149
* 2000 - 2134
* 2009 - 1241
* 2010 - 1693
* 2011 - 3312
WHAT AUSTRALIA OFFERS
* 18 weeks of paid parental leave - compared with 14 in NZ.
* Unemployment rate of 4.9 per cent - compared with 6.6 per cent in NZ.
* Higher average wage.
* Warmer weather in many states.
* First homeowners can get a grant of up to $7000 in Australia.
* Life expectancy at birth is 81.5 years - compared with 80.4 in NZ.