New border exceptions will allow partners and dependent children of temporary visa holders, who themselves hold visas, into New Zealand.
It is one of a number of exceptions announced by Immigration Minister Kris Faafoi.
Watch the announcement here:
The government is fixing an anomaly which meant migrant workers who entered the country before last year's Covid-19 border closure could not bring their families but those who came after could.
It has been reported that 5000 family members are affected by the rule.
Only temporary visa holders who were overseas when the border closed, but who normally live here, can apply to enter under the border exceptions.
Offshore visa applications for the families of healthcare workers are also covered under the exceptions, meaning once again these workers can apply to have their family join them in New Zealand.
In a 'limited exception' a small number of other highly-skilled non-healthcare workers will also be able to apply to bring their family here.
The family member currently in New Zealand needs to have more than 12 months remaining on their visa for their family to be eligible.
"We are in the midst of a global pandemic, which requires strict border restrictions. But we have been mindful of the difficulties migrant workers and families have faced," Faafoi said.
"In the past year, we have introduced exceptions that have allowed entry for around 13,000 family members of New Zealand citizens and residents and 1300 temporary work visa holders, and their families, who normally live here and were overseas when the borders closed. More than 2,500 family members of critical workers have also entered to date.
"These latest exceptions are expected to allow hundreds more migrants to come to New Zealand and join their families."
Border exceptions for those eligible can be requested from 30 April 2021.
Normal visa and managed isolation requirements apply.
There are around 6000 critical health workers currently and most would have come in after the border closure, Faafoi said in the media conference.
Around 450 people who had visas before the border closed still had relatives overseas, he said.
Asked how many migrant families would still be split even after these changes, Faafoi said he would guess it would be "thousands".
"I acknowledge there will still continue to be a signficant number of people who will continue to have difficulties within their families because they can't be put back together."
National Party immigration spokesperson Erica Stanford said today's news was wonderful, but there would still be thousands more migrants without any certainty.
"There was no mention of them, and there was no road map to reunification for those families. They don't expect it to be immediate, they just want some light at the end of the tunnel ... in six, eight months or in a period of time they will be able to be reunified as well."