Migrants are having a relatively small impact on Auckland's rising house prices, a new study says.
The research paper, commissioned by the Government, appears to contradict recent claims by Opposition parties and others that immigration is to blame for house price inflation.
The study instead concludes that the main drivers of rising prices in the city are low interest rates, investor demand, capital gains expectations and New Zealanders returning from overseas.
Any changes to immigration policy by the Government were therefore "unlikely to have much impact on the housing market", the authors of the Waikato University paper concluded.
Limiting new arrivals could even make the situation worse, they said, because it would reduce the number of skilled migrants required to ramp up housing supply.
The Ministry of Business, Innovation and Employment (MBIE) commissioned the research earlier this year to get a clearer picture of the effect of record migration levels on housing in Auckland.
Net migration levels reached 68,000 people in the year to June. A large proportion of arrivals are settling in Auckland, where housing demand is outstripping supply. That has prompted calls to curb immigration.
The Reserve Bank recently told the Government to consider reviewing its immigration settings to stem rising house prices.
The Labour Party and New Zealand First believe migrant numbers should be immediately reduced to ease the pressure on jobs and housing.
The public also appears to be in favour of new immigration controls. A Newshub poll released last night showed that 60 per cent of New Zealanders want the Government to let fewer immigrants into the country.
But the Waikato University study, which draws on existing New Zealand and international research, reinforces the Government's position that migrants are not primarily responsible for high house prices.
"Overall we find that ... visa-controlled immigration into New Zealand, and specifically into Auckland, in the recent past has had a relatively small impact on house prices compared to other demand factors," the study said.
"Consequently, changes in immigration policy, which can impact only on visa-controlled immigration, are unlikely to have much impact on the housing market."
The authors said growth in net migration was largely driven by student and temporary working visas, who were less likely to buy houses.
The fall in New Zealanders leaving the country in recent years has had much bigger impact on rising house prices in Auckland than the rising number of new arrivals, they said.
The study also found that migrant investors were not having a disproportionate impact on Auckland's housing market because they were mostly buying commercial property or a single house.
While the study did not look specifically at potential changes to immigration policy, it said any reduction in migrants could do more harm than good.
"It is plausible that any policy-driven reduction to the inflow of migrants to offset housing demand is likely to exacerbate skills shortages..."
Finance Minister Bill English yesterday ruled out any changes to immigration settings, saying that businesses were still facing skills shortages.
The regions and the construction and IT sectors were "crying out" for skilled workers, he said.
"We've got to keep in mind here that the biggest single driver is Kiwis staying home, and we regard that as a measure of success."
But Labour's housing spokesman Phil Twyford said this was "total spin" because returning New Zealanders made up just a quarter of net migrants.
The Government needed to "throw off its ideological blinkers" and cut immigration numbers, he said.
"The Reserve Bank couldn't be more explicit. There are economists almost every day coming out and saying the Government's got to look at the effects of immigration on the Auckland housing market."