It's been called the "original sin" of our no-fault accident compensation scheme, ACC. A system that divides people disabled by injury or illness into two camps: those who get compensation and rehabilitation covered by ACC and those who don't.
The haves and the have nots. The people who drive Rolls-Royces and the people stuck in Toyota Corollas.
The history of ACC is one of a two-tier system, and after almost 50 years of politicians, lawyers and disability advocates trying to get it changed, the systemic unfairness remains.
Andrew Dickson, who's been fighting ACC on behalf of his son for several years, says the system is unjust.
His son Ben was injured at birth and does not receive ACC compensation, but it's not just birth-related problems, or brain injuries, or medical misadventure there are problems with.
The issue with ACC funding impacts anyone with a disability related to an illness rather than an injury, says former Prime Minister Sir Geoffrey Palmer.
He wrote the original white paper about the ACC scheme after the 1967 Owen Woodhouse Royal Commission report recommended a radical - many believe visionary - revamp of accident compensation.
He says the original no-fault, earnings-related scheme solved the problem of it being a "forensic lottery" whether someone got compensation after an accident or not.
But limiting it to injuries has become "a new lottery".
"You are left with a massive anomaly. And that is that people who suffer from cancer or from other debilitating diseases are not covered by the accident compensation scheme. And you don't get the generous amounts of rehabilitation and compensation that scheme provides.
"You've got two classes of people in new Zealand who are disabled. Those from accidents and those from illness. And they are treated quite differently. And that is socially unjust."
Another ACC expert, Auckland University Business School associate professor Susan St John, says the fact ACC is earnings-related favours working people over people that don't work, high earners over lower-paid ones, and - often in practice - men over women.
"If you took the example of a high-flying executive male, going to work on his Lime scooter, and he causes an accident; he runs into a 60-year-old woman. And they both have similar long-term damage done to them.
"He ends up with $78,000 a year of excellent compensation."
But the woman isn't in paid work - she's a volunteer and looks after her grandchildren.
"She ends up possibly on a supported living payment of about $11,000 - if she's lucky. If she's married to somebody who's working, she might be entitled to nothing."
Geoffrey Palmer's Labour Government tried hard to expand ACC to cover sickness in the late 1980s. A bill was introduced to Parliament at the time, but when Labour was defeated at the 1990 election, the bill went too. National saw it as too expensive.
These days, the Green Party is the only one with ACC on its reform agenda. One of its 2020 election priorities was to change ACC into the Agency for Comprehensive Care, and give anyone with a work impairing health condition or disability impairing their ability to work the right to a benefit worth 80 per cent of the full-time minimum wage.
It's better than nothing, but it's not enough, says Palmer.
"I looked at it, but it's too mild for what's needed here. You won't get this through party political promises, you have to have a proper analytical approach.
"There needs to be another Royal Commission."