Public hospitals are poised to start paying back tens of thousands of staff for breaches of the Holidays Act.

They have been working for years with expensive consultants trying to unpick the tangle and bring in new payroll systems.

Te Whatu Ora Health NZ said it now expected payments to current staff to begin in July.

An estimated 270,000 current and former staff are owed money stretching back to 2010.

Health NZ did not provide an update of its liability which last November was put at almost two billion dollars, double the estimate of 2021.

Interim chief people officer Jim Green said teams across New Zealand were working to recalculate former and current staff holiday pay "as efficiently as possible, without compromising the process and outcomes".

"It is anticipated that we will be on a pathway to making payments to current staff, district by district, starting from July 2023.

"You will understand that we cannot be more specific than this at the moment, given the processes that need to be worked through prior to any payments being made."

Reform of the complicated Holidays Act itself has been delayed yet again, to after the election.