Split migrant families are being offered the chance to have their residence applications prioritised so they can reunite.
But advocates say their hopes of a solution have been dashed because of the criteria - and because fast-tracking will only happen once most of the slower groundwork has already been done.
Immigration New Zealand (INZ) has told migrants they can ask for their case to be expedited if their partner or children are still overseas.
Immigration adviser Katy Armstrong said it should have happened a lot sooner.
INZ would be relying on migrants to ask for the priority status, and there were still families whose cases would not be fast-tracked or escalated because of the policy detail.
"Immigration has explained they themselves can't identify who the families are so they have to ask families to come forward. Escalation seems to be - you can get priority once your application reaches a certain point which is called 'under assessment', but the problem is a lot of applications for unknown reasons are sitting in this new computer system and haven't reached that point.
"No one can really articulate clearly why that is. It sounds awful, but it's probably going to be another another queue."
She is worried that most affected families would still not be reunited by Christmas.
Fast-tracking the residence applications of all split families - even those who had recently managed to reunite - would go some way to 'righting the wrong' of not prioritising them from the start, Armstrong said.
Police checks
"Applications may progress to the Under Assessment stage only after police, character and other key checks are completed," said an email announcing the policy change to stakeholders. "These checks must be completed before we can action any requests for urgent processing."
Immigration adviser Julie Mariuzzo said it was the delays in getting to that stage that needed addressing.
She was disappointed in INZ's response to concerns over police check delays and problems in waiting for residence were affecting everyone in different ways.
"Lots of people are missing opportunities like job opportunities, study opportunities. We have had people who are just too scared to travel and go see their family until they are residents because they don't know if the borders are going to close again.
"Just general stress as well of waiting - people around them who get residence and they don't, so they're scared that there's something going on with their application, that they could get declined.
"And for some of my clients, they have had opportunities, for example, to be promoted in their own company or to change jobs substantially or to open their own business."
Changing job under a temporary visa meant a new application, expense and more uncertainty, she said.
INZ did not answer questions on whether police checks had been the main obstacle to residence visas getting to the assessment stage, nor what accounted for the slow-down in visa processing numbers.
It said 15,700 checks were still being processed by police and they were now being completed at an average rate of 4000 per week.
"The timeframe for 2021 Resident Visa third party checks, including Police and National Security checks, varies according to the nature of the application," said Michael Carley, acting general manager border and visa operations.
"An application may have multiple applicants or a check of one applicant may take longer than other applicants in the same application. Each application is unique.
"The time it takes to process an application depends on a number of factors, including third party checks, how long it takes for each processing task to be completed, whether manual assessment is needed, or whether we are waiting on information from an applicant."
Third-party agencies were committed to completing checks for 2021 Resident Visa applications as quickly as possible, Carley said, and INZ aimed to have the vast majority of residence visas decided by June.