Labour is taking aim at work visa and family reunification categories as it eyes ways to limit the flow of migrants to the country.
The party has come under fire over the idea, which first surfaced in its monetary policy as a way to help curb interest rate rises and house prices.
Prime Minister John Key went on the attack over the policy yesterday, even claiming he and his wife would not be in New Zealand if Labour's plan went ahead.
His parents were from Austria and Britain and wife Bronagh's parents were Irish. "Under David Cunliffe, I wouldn't be here and Bronagh wouldn't be here."
Key said Cunliffe wanted to "turn off the tap" but it was not possible. Some people, such as Australians, had the right to come here. "It would be a very knee-jerk reaction to go out there and all of a sudden say we are going to completely stop migration," Key said.
However, Cunliffe has not argued to stop all immigration. He has said it should be more tightly controlled, with the Treasury forecasting net inflows will top 40,000.
Labour immigration spokesman Trevor Mallard said there would be no change to the rights of Australians to come here, or to quotas under agreements such as with Samoa or the annual refugee quota.
Instead, it would target the numbers getting work visas, which according to Statistics NZ were granted to about 30,000 last year, as well as visas in the family reunification category.
Government data showed that last year about 11,000 were granted residency under existing family reunion categories.
In all, just over 71,000 migrants came to New Zealand last year. After taking into account those who left, that gave a net migration gain of 34,400.
Mallard said changing the flow of migrants was "not a fine-tuning tool" because there were always people in the pipeline. Changes to the Australian economy, which had a strong influence on flows across the Tasman, could happen more quickly than policy could adjust.
But altering the flow of migrants could be used to boost the economy as well as as a "counter-boom tool".
"The levers go both ways."
Cunliffe yesterday refused to put a number on what he would consider a sustainable flow of migrants, but he has pointed to net flows of 5000 to 15,000 in the past and said that could rise to 20,000 when there were a lot of Kiwis returning.
That would suggest a cut of at least 14,000 from last year's numbers. Cunliffe said immigration levels were "at the upper end of the spectrum" now.
Key said immigration figures were a "good-news story" and reflected a strengthening economy. Migrants brought much-needed skills to the Christchurch rebuild and projects like Auckland's Waterview tunnel.
Immigration was already tightly controlled. "It's actually quite difficult to get into New Zealand."
- The Dominion Post