By Gill Bonnett of RNZ
High pay is now among the reasons why officials are fast-tracking some applications.
More than 10,000 people are waiting for news on their visas.
Immigration New Zealand says an increase in applications has caused the residence visa category to be oversubscribed.
Yet figures show it is still 12,000 under its already-lowered maximum target of 60,000 new residents by the end of the year.
Immigrants are angry that other applications are also being prioritised internally by immigration officials for reasons such as jobs that need occupational registration and being over the high remuneration threshold of $105,000.
Immigration adviser, Brandon Han said prioritising very high wage earners over other skilled migrants was discriminatory.
"It's not a very smart idea to blindly generalise this as a threshold because, for some of the industries, the acceptable, industrial level of income is not high," he said.
"You can't expect everyone to qualify for that high amount of salary, it's unfair."
The situation would not improve until Immigration New Zealand (INZ) recruited more and better-qualified staff, he said.
One of those immigrants still waiting, who asked to remain anonymous, said she doubted her application would be approved until next year, to keep this year's numbers down.
She and her partner, both from the UK, applied for a residence visa under the skilled migrant category in January as a project administrator in telecommunications and marketing officer.
"We're just really not pleased what's been happening with INZ since like May and June, with the prioritisation of people who earn over a certain amount of money, and registered occupations being chosen before others," she said.
"You know we've all had to pay the same money, and we're currently just in limbo really."
They had explored the idea of moving to Australia instead, she added, but the $5000 they had put into the application was a lot of money to write off.
INZ was not being clear with customers about its aims of bringing numbers down, and how it is achieving that, she said.
"Residency numbers are down - well, of course, they are because they've taken people's money, and they're not accountable to any service level agreements, and we're just stuck."
Immigration figures show one in 10 will wait more than 13 months and a quarter more than nine months.
And immigrants say those figures are skewed by people being picked out of the queue for faster processing.
INZ said 120 officers were working on residence visas but it could not say how that compared to previous years.
Visa Services national manager Peter Elms said while applicants were understandably looking for fast decisions, residence visas need greater scrutiny than most applications.
"Sustained economic growth and low unemployment have driven significant demand for migrant workers at all skill levels," he said.
"New Zealand continues to be an attractive destination and application volumes have been increasing steadily across all categories. The Skilled Migrant Category is now over-subscribed. We are also seeing an increase in the level of risk and complexity in applications."