National has sparked a "populist bidding war" on immigration that threatens key industries such as tourism, construction and aged care, one of its support partners says.
Act leader David Seymour says the Government's announcement this week of a tightening of immigration rules had seen anti-immigration arguments become "even more farcical".
"By attempting to get tough on immigration, National has sparked a populist bidding war in which facts are completely ignored," Seymour said.
Immigration will be a major election-year issue.
Labour leader Andrew Little yesterday vowed to slash immigration by "tens of thousands" of new arrivals.
The party is expected to release policy in the coming weeks.
New Zealand First leader Winston Peters has long called for a drastic reduction in immigration, and labelled the Government's latest changes "tinkering".
The Green Party has also called for a reduction in numbers, releasing policy last year to cap overall net migration at 1 per cent of the population, including returning New Zealanders.
United Future Peter Dunne has echoed Seymour's concerns about the immigration debate, saying his party has been the only consistently pro-immigration party over the years.
Today he issued a press release telling Little it was "time for a calming cup of tea", and saying his comments is "xenophobic and divisive".
"Labour needs to stop the dog-whistle waffle and spell out clearly which migrant groups they have in their sights," Dunne said.
Seymour said there were areas where immigration rules needed tightening, but reducing numbers by the tens of thousands is impossible.
"These ideas would mean blocking all new work visas or cancelling our open travel arrangement with Australia or stopping expat Kiwis from returning home.
"Even if it were possible ... it would do enormous damage to key industries. Tourism, aged care and - crucially during a housing shortage - construction are all screaming out for new workers."
Record migration, which is underpinning New Zealand's economic growth and putting pressure on infrastructure, has shown no sign of letting up and in the year to February was at a net level of 71,333.
The Government has argued strong immigration flows are a measure of the country's success and contribute positively to the wider economy.
However, last October Woodhouse announced changes that meant those coming to New Zealand under the skilled migrant category would need 160 points before getting residency, rather than 140. The number of people allowed enter under the family category was also more than halved, and a temporary ban on applicants under the parent category was also announced.
And this week Woodhouse unveiled another raft of changes, the last planned before September's election, including restricting skilled worker visas to those who will earn more than $49,000 once in New Zealand.
Federated Farmers said those changes will make it harder for farmers to hire enough staff, and the horticulture and aged care sectors have raised similar concerns.
Changes to start from August 14:
• Anyone who will earn less than about $49,000 a year once in New Zealand won't get a skilled migrant category visa, and permanent residents won't get points for such jobs.
• People who will earn more than $73,299 will automatically be classified as highly skilled.
• The SMC points table, under which individuals claim points towards their residence application, will also be realigned to give more recognition of skill levels in the 30-39 age group and high salary levels.
• Limiting lower-skilled visa holders to a maximum of three years, after which a stand-down period will apply before another visa can be approved.
• Classifying the partners and children of these visa holders as visitors, meaning they will only gain work visas if they meet requirements in their own right.
• Ensuring the length of the visa in seasonal occupations aligns with peak labour demand, rather than for 12 months as is presently the case.