Fathers separated from their children by border restrictions are calling for the government not to forget their plight.

Split migrant families will spend another Christmas apart and are worried if they will even be reunited by the end of next year.

For almost two years, Wellington web designer Masthan Pathana has seen his wife and now seven-year-old son Affu only on daily video calls.

They had not spent a day apart until he left for New Zealand, and his wife and son were due to join him two months later.

"It was the happiest moment for my small family when we saw an email with approved visas, but we never thought New Zealand borders would close for such a long time, which turned our happiest moments into a nightmare.

"It's been two years now that I haven't given hugs to my son and wife. My son always asks me when can I come to New Zealand, he tells me every day 'I miss you Papa'. We three are getting emotionally weak, though trying to convince our hearts but still unable to stop the tears."

They have been turned down for border exemptions seven times, despite border criteria that are meant to favour families of highly-skilled workers. He said he had broken down in tears in a supermarket car park.

"My son is completely attached to me. He usually talks a lot to me on video calls and that is our unbreakable bond because I have a million things to do with him. And I had already been doing the same thing with him earlier in India. I used to play with him and even in video calls I play with him.

"Every night in bed, I am using my son's talc on my pillow to feel his fragrance, and listen to all his recordings, funny talks etc, If I don't do that I am not falling asleep."

To add to the missed opportunities, his new job started the Monday after the new one-off resident visa was announced, which means he and his family cannot be eligible for it.

That is despite taking a Masters course in New Zealand, earning double the median wage and watching fellow students on lower-level courses among the 165,000 migrants and their relatives who will qualify.

'He has kind of accepted that Dad's not around anymore'

The one-off resident visa will open next week, and many split families are eligible. But most can only apply from March, which has them worried about how much longer they will have to wait to be reunited.

Jonathan Richardson does qualify to become a resident, and at that point his wife Melissa and two sons can join him from South Africa. Cayden is 9 and Keeran turns 5 this week.

"It's been a rough road being separated from the family," he said. "The kids are just too young to understand why their dad's not at home. It's been really difficult with Keeran because he totally lost interest in the video calls and the WhatsApp phone calls.

"We've discussed this at length, Melissa and myself, but the impression I got is that he has kind of accepted that Dad's not around anymore. Which made it really tough as a father. He had just turned three when I left South Africa, and he's obviously just too young to process and understand exactly why we're doing this and why we separated."

They know they cannot be together this Christmas, he said, but are already worried about Christmas 2022. If he returned to visit them, his residence application would be put on hold and he might not get back into the country.

"The one-off residency visa has given us some form of hope to keep sticking it out but it's all still very uncertain on how long it will take to process our residency if we apply on 1 March 2022. INZ say they can take up to 12 months to process. We simply won't last that long. Our boys are struggling, they want me to come home."

An estimated 5000-7000 migrants still have family stuck overseas, immigration adviser Katy Armstrong said.

"We need to start treating people with fairness and respect no matter their paper status. Instead, our system gaslights those who are split from migrant families, making them think they are a threat to our Covid-19 response and 'less than'.

"We haven't heard any ministers talk about split families or split partners for a very long time. Yet these people are part of our communities and our Covid-19 response."

Having asked many times for such families to be given consideration ahead of allowing in tourists or students, it was disappointing to see a new border exception for 1000 international students, including 400 pilot trainees, she said.

They should be prioritised when the one-off residence programme opens next week instead of having to wait until March to apply. "If a family is here and together onshore, should they get priority over a family that is split?"

In a statement, Immigration Minister Kris Faafoi said the government was not currently considering any further options for split families.

"The 2021 resident visa will enable the majority of partners and dependents who are currently stuck offshore without a current border exception pathway to be included in residence applications, and if they are successful in gaining residence, they will subsequently be able travel to New Zealand."