Parents are spending up to 20pc of their income on childcare per child - and those in Dublin and East Leinster are among the worst hit.
A major think tank has warned that the amount of after-tax income spent on childcare in the years before children enter the State-subsidised pre-school scheme is a "substantial burden".
It costs the average family 12pc of its income for a childminder or creche to look after a three-year-old child, according to the Economic and Social Research Institute and Pobal.
This becomes 16pc for lone parents and 20pc for low-income families.
They say the burden is even bigger for larger families, as the figures are based on costs for just one child.
Families in Dublin pay 18pc more a week than those living in the Border region, for example.
Paying for childminders to work in the family home is the most expensive option, at €6.13 an hour.
Creches and nursery schools charge an average €4.82, with childminders based outside the family home the cheapest option at €4.76 an hour.
The report notes that Ireland is one of the most expensive places in the world when it comes to childcare.
It says that the OECD found we have one of the highest costs as a portion of income for pre-school children.
The researchers conclude that greater Government support to bring down childcare costs will increase the number of mothers in employment and give the State a tax boost.
The report reveals that:
The report says the average spend on childcare "poses a significant barrier" to employment for women.
Children's Minister Katherine Zappone said it would take a number of budgets to correct "decades of underinvestment".