Thousands of health workers may be owed millions of dollars because of years of underpayments under the Holidays Act.
But after three years trying to untangle the mess, the district health boards are still unable to say just how many of their 70,000 workers, and thousands of former staff, are owed how much.
A DHB annual review said the matter is the subject of a recent Auditor-General report and that "the matter might result in significant liabilities for some DHBs" in having to pay back workers ranging from cleaners and receptionists to nurses and doctors.
Such backpayments have already cost the police more than $45 million since late 2015, Corrections $16m, the Ministry of Business, Innovation and Employment (MBIE) perhaps $10m and another $20m overhauling its whole payroll system, and Auckland Council expects to pay out $18m this year.
But the DHBs are far from being in that position.
Their national organisation Technical Advisory Services (TAS) is handling it, however, when RNZ asked for figures and details, TAS said it "doesn't hold the information you requested".
"As the AG [Auditor-General] reported, this is a very complex and time-consuming matter ... DHBs are currently working on the matter at a sector wide level to assess the implications and possible solutions. We know this is a matter of interest and will proactively make announcements when we have sufficient information."
The Council of Trade Unions said its patience was running out.
"We need to make progress on this urgently," CTU president Richard Wagstaff said.
They had been seeking a negotiated solution for two years, rather than calling in the labour inspectors from MBIE to investigate the law breach.
"A day delayed is a day too long ... If in fact we can't make any progress, the labour inspectorate will just have to move in and do their thing," Mr Wagstaff said.
Maximum penalties under the law are $20,000 per breach for companies, and $10,000 per breach for individuals.
At least the DHBs had agreed to "stop the clock" so that any delays now, did not eat into how far back they would be reimbursed for, Mr Wagstaff said.
The police repayments covered 2004-2015 and 16,000 staff, who were owed an average of $1600; Auckland Council arrears extend back to 2010.
Health Minister David Clark declined to comment on the extent of the DHBs' liabilities, or if the government was budgeting to cover that.
But he said the previous government started looking at the issue in early 2016 and was never able to resolve it.
"The DHBs, of course, are not alone with this and it takes a long time to unpick. It is complex and my message is that I'd really encourage the DHBs, and the unions and those that are looking into it, to stick at it because we need to find a solution not just for the health sector, but more widely."
A major problem is that health workers are employed on over 100 different types of contract across a bewildering array of shifts.
It was a complex problem, beyond even what police faced to correct their underpayments, said Ian Powell of the Association of Salaried Medical Specialists.
"So it may take longer but it's still not excusable the length of time it's taking," Mr Powell said.
"The whole thing is proceeding at a snail's pace."
The "message of frustration" had been passed to the DHBs.
The picture is confused further at individual board level: For instance, Hawke's Bay DHB, according to its annual review, expects the problem to be resolved by this July.
Hutt Valley DHB, meanwhile, after a "self-assessment" reviewed by consultant PwC, said it had no liabilities.
Workplace Relations and Safety Minister Iain Lees-Galloway said paying back DHB staff was a priority.
"Of course we want to see these matters dealt with urgently," he said.
"It will take time in some cases but people who are owed money have a right to receive that money."
But he did not have a role in hurrying the DHBs along.
"My responsibility is that we have good legislation that people can work under and that the labour inspectorate is able to engage effectively with employers," Mr Lees-Galloway said.
"The DHBs have to take responsibility for dealing with these issues.
"There's a number of things this government is dealing with that we inherited from the previous government - the rates of pay, the conditions people are working under, and the situation with holiday pay.
A review of the Holidays Act is being done and he expects to get it back by mid-year.
The CTU said the previous government played down the payroll problems, but that the current government needed to fund the labour inspectorate at MBIE better so it could tackle Holidays Act underpayments that have still not been fixed at thousands of companies nationwide, despite first coming to light in 2015.
The minister said the inspectorate got extra funding in last year's Budget.
The latest MBIE figures, which are a year old, show the inspectorate has done 165 payroll audits since 2012, peaking in 2018; so far $19m in arrears has been paid to 34,000 workers, not counting the police payouts.
The Auckland Council has kept pushing back its reimbursement dates. It now expects to make final payments in October and November this year, to 17,500 current and past employees.
It paid consultants Ernst and Young $2.1m to audit the payroll to discover what was owed.
An Ernst and Young spokesperson has said the complexity of the work was unprecedented.