Documents obtained by RNZ show Immigration Minister Iain Lees-Galloway knew eight months ago that delays in processing residency applications were about to blow out.
Applicants say they were never told they could be forced to wait more than a year for a decision.
More than 37,000 people are waiting for news on their residence applications.
Among them is research and development chemist Yu Zheng, who does not fit immigration criteria to be in a priority queue.
But that does not mean his case is not urgent - if he does not get residence before June when he starts a PHD at Massey he will have to abandon his application as a skilled migrant.
He said he was granted a fully funded doctoral scholarship in chemistry and that too would be hard to give up.
He tried and failed to access an escalation process to shorten a 15-month timeframe.
Zheng said Immigration New Zealand was not listening to people who needed their cases dealt with quickly.
"I have attached another 20 documents to support my request. It's bad, it's bad for me. I spent a long time to prepare for that escalation request."
Other applicants who have contacted RNZ include those putting decisions on hold about having families, and not being able to change jobs.
One man has to decide whether to stay in the hope of getting residence - but the long wait time means he could face prosecution for avoiding military service overseas if his application is rejected.
A mother said her son was suicidal as high international fees prevented him studying while they were not residents.
Almost all spoke of how their immigration application was the first thing they thought of when they woke and the last thing they worried about going to bed.
In February, the government lowered the numbers of residents it wanted.
Immigration adviser Harris Gu said a May briefing to the immigration minister released under the Official Information Act showed he was aware then that that quota was almost full by those already approved and waiting.
He said the minister should have acted at that point, directing INZ to tell immigrants and advisers of the delays they would face.
"It's quite unfair for the applicants who submitted the application under the impression that the application should be processed very soon," Gu said.
"I'm pretty sure that they did not spend $3000 knowing their applications will be deferred or delayed for more than 12 months."
Immigration New Zealand said application volumes continued to increase across all categories and were more complex.
It said there had been no attempt to slow visa processing.
Lees-Galloway was approached for comment about the briefing, including whether he directed Immigration New Zealand to tell applicants of the residence programme and subsequent processing delays.
In a statement, a spokeswoman said it was Immigration New Zealand's job to advise applicants of timeliness.
She said officials had not been asked to reach the lower end of the 50,000 to 60,000 residence target.
With one month to go before the current residence programme ends, 49,869 resident visas have been issued.
The number of residence decisions has fallen from more than 44,000 to fewer than 37,000 in a year.