Watch out for unsubstantiated slurs and hysterical hyperbole in the migration debate, the race relations commissioner says.

So, we asked who's really coming to New Zealand?

It's mostly under-35s with work visas, including working holidays, international students and returning Kiwis and Australians.

Migration is at an all-time high but the real story behind the rhetoric and "concerns" about migrants is a spike across the three main categories of work visa, mostly Europeans, and more students from India and China.

NZ First leader Winston Peters has suggested annual immigration should be capped between 7000 and 15,000 "seriously qualified" migrants and Labour has called for a cut in work visas.

Race Relations Commissioner Dame Susan Devoy said immigration was a policy issue all New Zealanders had a right to discuss, but facts, not hysterical hyperbole, were needed.

"Winston's platform is about giving people a fair go but he needs to walk his own talk: he implies that migrants coming to live here do not obey New Zealand laws but where is his evidence to support these claims?

"We are 18 months out from a general election and we are hopeful that Kiwis will demand accuracy from our politicians, and not be satisfied with unsubstantiated, sweeping slurs."

WORK, STUDY, SETTLE

The widely quoted figure of 124,000 migrants is not the number of people newly arriving in New Zealand to work. 

Net gain, the figure roughly representing the number of people here to study and work, is the sum of arrivals and departures minus the number of departing residents and overseas visitors leaving after staying for 12 months or longer.

That figure is 68,100 for 2015/16.

To put this in perspective, the number of short-term visitors, including tourists, in the year to April was 3.2 million.

Of the 68,100 migrants, 42,220 arrived in the North Island in 2015/16, 10,336 went to the South Island while another 15,524 were not identified by region.

In 2015/16, there were 38,825 people issued work visas, 36,475 Kiwis and Australians arrived and 27,645 people arrived to study.

The majority of migrant students, who can work part-time, are Indian and Chinese while most working holiday visitors hail from the United Kingdom, France and Germany.

Work visas were mainly issued to people from the United Kingdom, France, Germany and Australia, while student visas were issued to citizens of India, China and the Philippines. Most new residents hailed from China, the United Kingdom and Samoa.

The most common jobs for those issued work visas, which include working holiday visas, are in hospitality, the food trade and engineering and the regions with the highest gains in populations were Auckland, with 26,800, and Canterbury, with an increase of 6400.

NO 'WAVE OF MIGRANTS'

Immigration Minister Michael Woodhouse said it was a popular myth that migrants went to Auckland to work when the jobs were in places like Nelson, Marlborough and Canterbury.

Skill shortages and labour shortages were regionally specific. A decline in skill level cited by the Treasury related to increasing numbers of people in the essential skills category with diploma-level qualifications rather than, for example, degrees or postgraduate qualification.

Interviewing people at the border or capping numbers in certain classes was nonsense, he said.

"The jobs are in Southland, in horticulture, the fishing industry. It's true the numbers have grown. The economy has grown.

"The skill movements are quite understandable in the context of the way in which our visa policies work to meet demand, to meet shortages.

"If I wanted to turn the tap off we could kick 20,000 working holiday people out but do you really think our burgeoning tourism industry would be better off?

"This stuff is complex.

"Kiwis need to be at the front of the queue. To suggest there's a wave of migrants taking our jobs and buying our houses, it's just nonsense."

POPULATION FLUCTUATES

University of Waikato professor of population economics Jacques Poot said net inward migration was at a record level but this needed to be considered relative to the country's population.

Migration was a "cyclical rollercoaster" in terms of pinpointing figures, although the level was likely to fall in the next few years.

The number of people who are in New Zealand constantly fluctuates with births, deaths, arrivals and departures.

"Although it varies strongly seasonally, we have an upward trend in the number of visitors...so the "de facto" population goes up even without more long-term migration.

"In terms of migration, we have seen a sharp drop in New Zealanders leaving for Australia, an increase in New Zealanders returning from Australia, an increase in people on work visas of 12 months or more and an increase in the number of foreign students.

"All these things combined have led to the currently high population growth rate."

The rate of population growth - 2.5 per cent - was high for a developed country and similar to growth around 2003 and in the 1950s and 1960s, another period when there was an increase in migration

In the year to March, 5.88 million people arrived in New Zealand and 5.78m left. This left an extra 95,129 people on the ground, Poot said.

"The volatility is not surprising when you think that the total number of arrivals in and departures from New Zealand run at roughly 5.8 million per year each, so that the difference between these two large numbers easily jumps up and down."

Migration was better measured over a long time and previous data show net migration contributed to a quarter of population growth between 1951 and 1976 and half of population growth since 2001.
 
(Source Stuff, John Edens)