The Government's lead business agency estimates 50,000 Kiwis will leave New Zealand as the international border reopens.
In a briefing to ministers in February, the Ministry of Business, Innovation and Employment (MBIE) said its "initial estimate" was that "roughly 50,000 New Zealand citizens might choose to emigrate over the next year as our borders open".
MBIE said it could be "possibly more if pent up OE [overseas experience] demand is realised over the next year, or less to the extent that New Zealanders delay their emigration plans until the international context settles".
The Government announced last month that, after two years of being locked away amid the COVID-19 pandemic, the international border would finally reopen to Australians from April 12 and visa waiver tourists from May 1.
But with rising demand for labour, MBIE has warned that Kiwis are likely to venture overseas for work and temporary migrants in New Zealand who do not qualify for the 2021 Resident Visa will return home or find work elsewhere.
"We expect Australian employers will recruit more actively in New Zealand as our borders open, offering workers higher wages than are available locally," the MBIE briefing says.
There is already evidence of Australia seeking to scoop up workers. The Australian Labor Party has pledged to have registered nurses in aged care facilities around the clock, prompting concern about a brain-drain from New Zealand.
Shortages of nurses is already a major issue in New Zealand.
"Labour's cost of living crisis is encouraging Kiwis to flee to greener pastures, causing a brain drain that we can't afford," ACT leader David Seymour said on Tuesday.
"Labour's chickens have come home to roost. By locking the economy down and borrowing $50 billion they have left us with a mountain of debt and rising prices. Kiwis are finding it difficult to make ends meet and are heading offshore for a better chance of getting ahead in life."
Seymour said Kiwis can't be blamed for seeking out Australia when the average wage is $38.52 compared to $27.76 in New Zealand.
"Rents are up, mortgage rates are on the rise, the cost of food is up, petrol is up, but wages aren't keeping up. What is Labour doing to make this a more attractive country for young New Zealanders?"
Prime Minister Jacinda Ardern on Tuesday responded to questions from Seymour in Parliament about MBIE's briefing. She said Kiwis leaving New Zealand for overseas experiences has been "part of our history".
"I note with interest the question comes from a member who spent some time in - if I recall - Canada and is being asked to myself who spent some time in London. It has been part of our history as a nation to frequently have New Zealanders come and go as part of our overseas experience, building skills and talent."
Seymour fears a brain-drain similar to after the 2008 Global Financial Crisis.
Ardern said the Government is focused on ensuring businesses in New Zealand can access the workers they need.
"We know that there's more to do on that front but unlike the member's perspective of New Zealand, New Zealand is a very highly desirable destination for workers and that's why we've already seen thousands of people applying for working holiday visas to come to our shores."
The Government on Tuesday announced 1580 additional border exceptions for workers in the dairy, meat processing and forestry industries.
"New Zealand's food and fibre sector continues to show its resilience and ability to adapt and respond to the challenges brought about by COVID-19, but extra help is needed," Agriculture Minister Damien O'Connor said.
But National's immigration spokesperson Erica Stanford said it's not enough.
"Rather than opening up the border to desperately needed workers across multiple sectors, the Government is picking winners and deciding who gets skilled workers based on who has the best lobby group," Stanford said.
"Why are we relying on a fairly small number of border class exceptions to fill skills shortages when the whole country is crying out for workers?
"While we are happy for the selected industries, which all desperately need workers, the announcement will do nothing for huge sectors of the economy which face major worker shortages."
