More than three-quarters of parents in Wales use unpaid family or friends to care for their children, new figures have shown.
Statistics Wales figures revealed 49% of parents with children up to the age of 14 use childcare - and 77% of those said their child was looked after by family or friends for free.
Charity Chwarae Teg said this was "not necessarily out of choice".
The Welsh Government said it was committed to helping working parents.
The figures, in the National Survey for Wales 2014-15 Childcare, were published on Thursday.
The report stated that 51% of childcare provided by family or friends was for between one and 10 hours a week, while 32% was between 10 and 30 hours.
Six per cent said that family and friends looked after their child for at least 30 hours per week.
Joy Kent, chief executive of Chwarae Teg, which supports women in work, said parents relied on family for childcare because it was "accessible and affordable".
"In the conversations that we have with woman, childcare comes up as the number one barrier in terms of their engagement with work," she said.
"They do rely heavily on informal support networks and it's not necessarily out of choice.
"There is also an issue with older women being in a position where they are looking after older members of the family as well as their grandchildren.
"They are a sandwich generation who have had to change their lifestyle and expectations as a result of this."
She said the majority of political parties in Wales had childcare provisions in their manifesto, and the charity was "anticipating" the Welsh Government would soon make it a "key focus" of their agenda.
Lynne Hill, policy director at Children in Wales, said the figures were "quite worrying".
"It's a challenging time for parents trying to maintain a work/life balance," she said.
"I understand that childcare is expensive. It's because people are providing a quality product in a quality setting."
But the expense, she said, was forcing families to make a difficult decision about how they were going to "make ends meet", particularly during the summer holidays.
She said: "For many it is family and friends that provide back up childcare."
Mrs Hill added that parents of children with disabilities faced additional problems when it came to finding suitable childcare.
The report also showed that 46% of parents found it difficult to afford childcare - which increased to 52% of those with children aged three or four.
At the same time, 40% with a child aged five to 14 found it difficult to get childcare during the school holidays.
The Welsh Government said it recognised the importance of affordable and accessible childcare.
"This is why we have committed to offer working parents 30 hours a week of free early education and childcare for three and four year olds," a spokesman said.
"Work is already under way with local authorities, parents and providers to develop and deliver the offer and the first pilot schemes will be rolled out in September 2017."
-reprinted from BBC News