Parents are facing increasingly high childcare costs, with nursery fees costing as much as £200 a week per child, the Daycare Trust has found.
The Daycare Trust says government must do more to help parents
The trust said parents could spend a third of their weekly earnings on fees.
Average fees in England for a full-time nursery place for a child under two were £152, rising to £205 in central London. Parents in Wales paid £131.
The government said it was working to reduce the cost burden on parents through the tax credit system.
The Daycare Trust surveyed 122 out of 172 Children's Information Services in England and Wales.
Two-thirds said that parents reported a lack of affordable childcare in their area.
The trust said parents in the UK paid around 70% of the cost of childcare, compared with European parents who paid around 30%.
Alison Garnham, joint-chief executive of the Daycare Trust, said the government should provide cash to help parents pay childcare bills.
"With typical childcare costs rising to over a third of average earnings, parents cannot afford to bear the burden of increasing childcare costs alone," she said.
"Despite significant Government investment in early years and childcare, funding childcare needs to be further improved so that all children have access to high quality, affordable and accessible childcare."
Children's Minister Beverley Hughes said: "We do appreciate the impact that childcare costs can have on the family budget of lower income families but we are doing more than ever before to make good quality childcare and early education accessible and affordable.
"We are providing more than £2m a day through the tax credit system to help almost 400,000 families.
"We are also investing £3bn per year to support free early education, so all three and four year olds can benefit from 12.5 hours a week free early years provision, irrespective of the employment status of their parents."
But shadow education minister Anne McIntosh said the costs for pre-school children in England were continuing to rise steadily.
"It is essential that all children have access to high quality and affordable childcare," she said.
Liberal Democrat children and family spokeswoman Annette Brooke said: "The escalating cost of childcare is a daily worry for thousands of parents across Britain. Childcare is fast becoming a luxury item.
"Both the government and employers need to do more to make returning to work a more affordable prospect for parents."