A tribunal has backed a woman in a decade-long fight over laws that cut her ACC (Accident Compensation Corporation) payout from $40,000 to just $500.
The Human Rights Review Tribunal has ruled a section of Social Security law is discriminatory.
Maree Hennessy, a mother-of-two originally from Waikato, had her ACC payout in 2010 cut to almost nothing because all her welfare benefits were deducted from it, under the government's "one benefit" principle.
The new ruling does not get her any more money, even though the Ministry of Social Development agrees with it, and wanted this declaration to avoid the need for more litigation.
"For those of our clients who are receiving income support from us and compensation from ACC, we are unable to make any change in practice despite the Tribunal's finding," the ministry said in a statement, adding it must implement the law as it is.
Ms Hennessy was too ill to talk to RNZ.
Lawyer Greg Robins, speaking on her behalf, said she regarded it as worth fighting for anyway.
"It's always going to be a landmark declaration of this sort ... it's clear and it's unequivocal and it places the issue squarely on the agenda," Mr Robins said.
About 600 other people currently get both income support and ACC so might be hit by the law, which has been in place for decades.
"It is disappointing Maree won't receive a backdated payment," said Mr Robins, from the Office of Human Rights Proceedings.
"But she was aware of that and so were we. This was the best outcome we could have hoped for."
The big sum she misses out on would have gone a long way to alleviating her situation, he said.
"She has fallen on hard financial times and despite those hard financial times and her injuries, she has kept on battling for this case and for that we are really appreciative."
Ms Hennessy was injured in 2002, and first fought ACC for coverage.
When she got the eroded payout in 2010, she then argued and lost at both the district court and Social Security Appeal Authority that her circumstances had been wrongly assessed under the law.
This Human Rights Review Tribunal ruling has now found the law itself discriminates on the prohibited grounds of "employment status".
The government has until later this month to appeal the ruling, or until June to respond to it.
Minister of Social Development Carmel Sepuloni tabled a two-page report on the problem in Parliament in December.
She told RNZ she had raised the problem of ACC and benefits with the Welfare Expert Advisory Group.
The independent group is due to report back at the end of this month, which could lead to law changes.
However, the Social Security Act was already altered just last year, and this discriminatory feature remained in place.
"The intention of the 2018 change was to simplify the law not to make any fundamental policy changes. Changes of this nature would have been significant ones," MSD said in a statement.
"The intention was always to look at more significant policy changes on a longer time frame."