Unions, lawyers, and politicians who have been trying to warn the government of the shortcomings in the Accredited Employer Work Visa say it should not have take a whistleblower to spring it into action.
Immigration Minister Andrew Little has ordered an independent review into whether the scheme is working as it is supposed to after an internal whistleblower tipped him off about checks on employers not being carried out properly, leaving migrant workers vulnerable to exploitation.
When New Zealand's borders re-opened last year, the Accredited Employer Work Visa was a cornerstone of the government's immigration rebalance.
In the rush to attract migrant workers amidst a global labour shortage, the government put in what Little said was a "low level" of checks.
"We made a deliberate decision for what we've described as a light-touch regime, but it wasn't a no-touch regime," he told Morning Report.
Little said officials had assured him the appropriate checks were being carried out, but the whistleblower's letter on Tuesday was enough to convince him to ask the Public Service Commissioner to set up a review.
"I don't leap to any conclusions. A claim has been made about the checking process. The correspondence I received, although it was anonymous, was credible enough for me to take it seriously, and I now want that verified," he said.
Union Network of Migrants president Mandeep Bela welcomed the review but said the holes in the system had been plain to see - it put too much trust in employers.
"There are a lot of good employers out there as well, but it does not mean we can put a blind faith and just simply approve accreditation without doing the checks and balances. The result of this, what are we seeing, is a core level of complaints coming through from migrants who are being exploited under this visa scheme," he said.
Bela said it should not have taken a whistleblower for the government to sit up and take notice.
"They could have contacted the relevant organisations to hear about our views and get recommendations."
Immigration lawyer Alastair McClymont had warned the scheme was ripe for exploitation since before it even started.
He told RNZ that employers only had to self-declare they were financially sustainable, and that they were operating proper wage and time record systems.
"The employer only has to answer a question in the accreditation form 'have you made a loss in the last two years?' So you can make one dollar's profit, and then bring in $600,000 worth of migrants. And if you can't sustain that financially, then this is why you've got these migrants who were dumped on the street with no jobs and no income."
McClymont said Immigration New Zealand was not staffed or resourced enough to undertake the verification checks it probably wished it could, but successive immigration ministers had been reluctant to take advice from migrant advocacy groups and lawyers.
"When you have a minister who will only listen to his civil servants, and refuse to go and talk to anyone else who's actually working in the industry, then they come to believe that the sole cause is other people, and not bad policy."
National's Immigration spokesperson Erica Stanford said the system was essentially operating on a "pinkie promise", and was failing to properly check documentation or risk factors.
She said she had told three successive immigration ministers the bureaucracy and red tape was in the wrong place.
"It's been happening under everybody's nose. Everybody knows about it. I know about it. Agents know about it. Lawyers know about it. The only people who didn't know about it, clearly, are the three ministers."
She a review was not even necessary.
"The review will find that there has been a general instruction delivered by Immigration New Zealand which says 'stop verifying documentation'. I can tell the minister that in five minutes, he doesn't need a review."
In a statement, Public Service Commissioner Peter Hughes said it was an "assurance review": checking the policy was working as designed, rather than assessing the policy itself.
As of 14 August, some 80,576 Accredited Employer Work Visa applications had been approved, for 27,892 accredited employers.
Bela said good employers should have nothing to worry about, and he did not want to see the scheme shut down.
He wanted the review to take the "bad eggs" out of the situation.
"We don't want any of the migrants to go through exploitation. We also don't want the system to be put into question but at the same time we want those employers to be held accountable, those who are using the immigration system to exploit these migrant workers."
In a debate at Parliament this month, Andrew Little admitted there would be rogue employers but the system had been set up on the basis most employers try to do the right thing.
"If any of those employers have made declarations that turn out to be incorrect, then there are penalties on that employer. So it is not in their interests to be misleading Immigration New Zealand," he said.
Immigration New Zealand declined to be interviewed, but said it supported the review.