The day the borders shut in March 2020, the chance to start a new life in New Zealand came to an abrupt end for many people. 

"I had a family who literally sold everything," says immigration consultant Katy Armstrong. 

"They'd done that based on a job offer here in New Zealand. They were due to fly just after midnight that March 19, the date that's etched in my brain and it will never go away." 

The family were on their way to the airport when they had to turn back. For Armstrong, the day was like an "eclipse of the moon" as she realised just how many thousands of migrants and would-be migrants would be

impacted by the border closure. 

Massey University distinguished professor Paul Spoonley describes it as a "zeroing out " of migrant arrivals. Except for a few special cases, all of the country's major visa categories were suspended, including the

important skilled migrant category. 

That unprecedented shutdown exposed New Zealand's heavy reliance on migrant workers in the labour force, says Spoonley. 

"We'd become addicted, if you like, to migrant workers as a very important source of labour in this country. I think what Covid-19 has done is shown how vulnerable our labour market is when we don't have any migrant

workers coming in." 

As the Productivity Commission prepares to release its final report on immigration at the end of the month, ahead of an announcement by Immigration Minister Kris Faafoi, The Detail looks at what's happened to migration

and what needs to change. 

Armstrong explains how some of her clients were stuck overseas and unable to return to their New Zealand homes, despite holding valid visas, while others were split from their families. 

"You had some onshore here already and some offshore who had been fully in the process of coming to New Zealand together, but the wall came up." 

Despite the staged reopening of the border this year, she says some will face another Christmas apart because of long processing delays. 

Spoonley says the Productivity Commission has been charged with looking at what a sustainable level of migration would be, that doesn't put undue pressure on things such as the housing market. 

The commission will also look closely at our reliance on temporary migrant workers. 

"Five percent of our labour force were temporary migrants. [That’s] very, very high compared with other countries. Australia's is three percent," Spoonley says.

That raises an ethical issue. 

"If you bring them to New Zealand to work on a temporary basis, should you allow them the opportunity to transition to permanent residency?" 

Last year, the government announced a one-off resident visa to let up to 165,000 migrants stay in the country. Spoonely points out there were 300,000 migrants in the country at the time. 

"Were we bringing them here under false pretenses? Were we paying them enough? Were we making sure they weren't exploited? 

"All of those issues need to be on the table in terms of considering what our future rate, either of permanent migrants or temporary migrant workers should be."