Despite the number leaving New Zealand to live overseas slowly rising, the number coming continues to climb resulting with a net gain of 6100 for the month of March alone.
Spoonley said "anxiety levels" had also gone up as a result of the high migration numbers, and that an "informed debate" was needed on the issue.
"I thought last year when the Government made those adjustments - suspension of the parents category and the increase in points - would see numbers drop, but that hasn't happened," Spoonley said.
"Now we have the latest round of policy changes...and I don't think the Government fully understands what its implications are."
According to Statistics New Zealand, 129,500 people came here intending to stay for at least 12 months, up 5400 on March a year ago.
Even with a drop of 9400, the largest number of arrivals still came from Australia, on 25,557.
This was followed by about 15,000 from the United Kingdom, 12,358 from China and 9547 from India.
The figures are based on arrivals cards details and did not provide details of citizenship.
About 5500 people did not state which country they had arrived from.
Work visa arrivals continue to be visa type contributing most to migrant arrivals, up 5100 to 43,700.
The number of New Zealand citizens and residence visa arrivals were also up 1300 and 2000 respectively, but student visa arrivals dropped by 3800 to 23,900.
"We have seen a drop in international students, particularly Indian students, but that's countered by an increase in the number of arrivals from countries like the USA," Spoonley said.
The number of arrivals from the United States are up 5700.
Immigration Minister Michael Woodhouse this month announced changes to the skilled migrant category.
This included a new salary thresholds, but it was not clear what difference the changes would make.
"The new income threshold is going to make it very difficult for a whole group of people who would not meet the $49,000 income," Spoonley said.
"Those are going to be in tourism, hospitality, health care and possibly some skilled professions like education."
Angry Auckland Thai business owners met on Wednesday to discuss a response to the proposed changes.
"We are just being made scapegoats of this election year," said Songvut Manoonpong, owner of Mai Thai restaurant, which has been in operation for 28 years.
"Most Thai restaurants are dependent on migrant workers, but we cannot pay $49,000 to every staff and still keep our businesses afloat."
Gaye Fasher, owner of Cocoon Thai Spa said it would be almost impossible for her five therapists to renew their visas under the new rules.
The group will be meeting the Restaurant Association today to discuss its response to the policy.
Immigration has also been blamed for pushing up house prices and suppressing local wages.
Labour, Greens and New Zealand First have also indicated that they intend to reduce the levels of net migration.
Population statistics senior manager Peter Dolan said the rising number of migrant arrivals and few migrant departures had contributed to a steady increase in annual net migration since 2012.
Immigration lawyer David Ryken however felt using data from arrival cards was not a good way to assess work visa levels.
"Those immigrants working here include many who arrive on visitor visas, who then apply for student visas and then work visas," he said.
"Take the Chinese and the Indians...at the border they were classified as 'visitors' or 'students', when they switch, they do not fill a new arrival card."
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