Immigration New Zealand's services have become inefficient and substandard after it shut down drop-in centres, those working in the industry have said.
The department said it's receiving 60 percent more calls than it can handle and that's meant average wait times on their phone lines are 44 minutes long.
One customer told RNZ yesterday it took two days for him to speak to a representative.
An Auckland-based immigration lawyer with more than 20 years' experience, Richard Small, said Immigration New Zealand's decision to close its global offices, and its front counters here, is putting pressure on contact centre staff.
He said that's making it hard for people to get the right advice.
"We are hearing staff [are] way out of their depth in these calls.
"The worst example was where someone was told that they were liable for deportation when they weren't - the partner of a New Zealand citizen - and they went back wrongly to their home country."
Another experienced immigration advisor, Arunima Dhingra, agreed the quality of advice coming through the call centre is questionable.
Ms Dhingra said you could call the contact centre twice and get different answers to the same question.
"We as a practice do not encourage our clients to ring the contact centre at all. I would much rather a client go to the website and see the information themselves and read it, or we tell them to ring the contact centre three times and if you get the same answer all three times, then there is probably some weight in that answer. But really that is a major issue."
Mr Small said the online system is useful, but it can't do everything.
Obligations to provide a public service mean the drop-in centres should be re-opened, he said.
There's just one left in the country, in Auckland, but it will close at the end of the year.
"When I visited that the other day it was packed ... and yet we've been hearing how almost nobody was using them, how they were really unnecessary."
A number of changes to post-study work visas are due to kick in from 26 November.
Arunima Dhingra said those changes are good.
But she said for migrants, the lack of information is causing confusion.
"I've got no qualms in saying that it is all over the show - you imagine a poor migrant who's studying here, invested thousands of dollars ... if that person doesn't know what's going to happen to him in the next two months, imagine the anxiety that that person is going through, imagine what the family's going through.
"They don't know if they have to sell off their car, sell off all their belongings and go back, or if they actually need a job offer."
Immigration NZ's director of operations for visa services Peter Elms said it's peak time for visitors and students to be applying for visas and that's what's pushing up demand - not drop-in centre closures.
But 70 percent of calls come from people within New Zealand wanting to check up on the status of their application, he said.
"Many people still want to contact us in advance of that date of completion, and that's where the volumes come into the contact centre, that's what causes the delays, so a little bit of this is about customer education, it's about telling people please be patient, bear with us, we will be in touch with you if we need additional information."
Immigration NZ is working to move most of its services online as quickly as possible, Mr Elms said.
Staff are well-trained and do the best they can, he said.