The Taskforce on Care Costs, comprising of business groups and peak non-government bodies, released an affordability index on child care on Friday.
The study follows the price of child care since December 2001 and shows its affordability has dropped by more than 50 per cent.
"If child care costs continue to rise at a rate faster than incomes, childcare will become too expensive for the average family and many more parents will consider leaving the workforce," the report said.
One in four parents have already reduced their working hours because of the high cost of child care, the study shows.