Mothers who face high childcare costs work fewer hours.
That's according to new research from The Economic and Social Research Institute (ESRI) and Pobal.
They found parents spent an average of 12% of their disposable income on childcare for their three-year-old.
It says this poses "a significant barrier to employment for women", especially lone parents.
For those who pay, it says the average hourly cost of care for one child was €4.50 at the time of the Growing up in Ireland survey in 2011, or €4.84 in 2017 prices.
The report found that, all else being equal, mothers with higher childcare costs at age three tended to work fewer hours when their child was aged five.
Costs were higher for those living in Dublin, East Leinster and other urban areas.
The financial burden was greatest for lone parents, who spent an average of 16% of their disposable income on childcare and for low-income families, who spent 20% of income on care.