Current and former police staff are owed about $40 million.

The problem was uncovered during a 2014 review of the payroll system.

It found a number of issues since 2009 resulted in staff receiving incorrect payments.

It relates to the payment of statutory holidays and pay rates for annual, sick and bereavement leave.

A plan's has been made to pay the money back over two financial years.

Police National Headquarters spokesperson Fiona Michel said it's too early to confirm the exact numbers of staff affected, the range of payments to be made, or the total sum to be paid to staff.

She said the money will be paid over two years and police are committed to doing the right thing by staff.