Community Law says it is 'blown away' by the wide-ranging effects of its win in a High Court immigration case.
But it wants faster action on visas for Afghans in dangerous situations in their home countries.
Immigration New Zealand (INZ) announced last week 4000 new residents can travel here and it will restart processing more than 5000 residence applications from migrants overseas.
That followed a High Court ruling that INZ was wrong to stop processing the visa applications of a group of Afghans due to Covid-19.
Community Law chief executive Sue Moroney said the number of people who may benefit from the case was staggering.
"It's been such an important court case, because it's just reminded Immigration New Zealand and other government departments that even in these difficult times to navigate, they've still got to apply the law," she said.
"We were trying to forewarn them last year that if humanitarian crises broke out over the period of the border closure, there would be some real problems with unprocessed visas and people stuck in dangerous situations
"The second reason we said to them was if you start processing and completing those visas now, you won't then face a logjam when you decide to open the borders up. Both of those things have come to pass, and sadly, instead of taking our advice a year ago, they've sat on their hands and waited until the High Court has instructed them that they have to do this and that in fact, what they had done at the outset was unlawful."
Waikato Community Law centre in particular led the case, she said, with lawyers working pro bono.
"We're blown away that a cash-strapped NGO like Community Law can take on the might and the resources of Crown Law and win a really important case that has lifesaving effects for many, many people. I think it's a really big win for access to justice for a group of clients that could never have afforded to have employed lawyers to run a High Court case for them in this manner."
But Afghan visas were still being processed very slowly, she said.
"We are really frustrated at how long it is taking Immigration New Zealand to process and grant those visas despite the court judgment that came out three weeks ago now. These are still life-threatening, urgent situations that the people in Afghanistan in particular are facing, and they are facing that because the New Zealand Government through Immigration New Zealand acted unlawfully and stopping the processing of the visas.
"There's a really high level of obligation on the Government and Immigration New Zealand to pull out all stops to undo the harm they have done."
INZ said it had been implementing Government policy to limit the number of arrivals into New Zealand to reduce the spread of Covid-19, and believed it was complying with all relevant legislation. "INZ accepts the Court ruling and will now complete processing residence applications from offshore received prior to the border closure in March 2020," it said in a statement.
Four individuals covered by the two applications at the centre of the High Court case had since been granted residence as an exception to instructions, it said.
"INZ has now completed an assessment of the remaining 17 Refugee Family Support Category (RFSC) applications, although it may take some time to finalise the applications as we need further information for some of them before we can make a decision," said General Manager Border and Visa Operations Nicola Hogg, "We will be in touch with their representatives this week.
"INZ resumed processing, but not deciding, RFSC and business category residence applications in late 2020. This approach is to make progress on applications so that decisions can be made faster once border restrictions are lifted."