McDonald's workers past and present look set for a payout, after faulty payroll systems incorrectly calculated their holiday pay.
Unite Union national director Mike Treen says the incorrect payments could apply to workers as far back as November 2009.
"Unite Union believes that could be as many as 60,000 staff and millions of dollars will be involved," Mr Treen said today in a statement.
Other Kiwi companies using the faulty payroll system have only chosen to provide remediation dating back the legally required six years, Mr Treen says.
McDonald's spokesman Simon Kenny confirmed the remediation process has begun at their end.
"We have spent tens of thousands of hours working on what is a hugely complex project, in order to ensure the approach to making calculations is correct," Mr Kenny told Stuff.
"With the agreement in place we can now start the process of doing individual calculations.
"As other companies working on annual leave remediation have done, we will advertise when we have worked through the calculations and will have a website current and former employees can log into."
Last month, the Government announced it will pay up to $650 million to fix long-running holiday pay deficit for DHB workers.