Significant gaps in the provision of emergency, out-of-school, and holiday childcare provision across Wales have been highlighted in a review.
The Welsh Assembly Government looked at data collected in 22 council areas.
There are also fears that the situation could get worse because budget cuts and changes to the benefits system mean more parents are looking for provision.
The assembly government said: "The needs of children and families are extremely important".
Under the Childcare Act 2006, every council is obliged to undertake an assessment of the sufficiency of childcare in its area.
The findings come in a review paper to the assembly cabinet by deputy minister for children Huw Lewis.
The review, from a cross-departmental working group, found a lack of understanding about exactly where childcare is needed to support employment, and little support for disabled children, or those with additional needs.
Blaenau Gwent has the least provision, with just one childcare place per 23 children. Next come Neath Port Talbot and Rhondda Cynon Taf.
Consultants for Blaenau Gwent council estimate that parents who can't work in the area because of childcare difficulties cost the local economy £4.8m in earnings alone.
David Dallimore, director of Melyn Consulting, which specialises in supporting local authorities with their childcare responsibilities, said it is a difficult area for councils.
"Local authorities don't generally provide childcare so it's a very strange duty when they are required to manage the childcare market when they don't provide it themselves," he said.
"But there are definitely gaps in childcare across Wales, particularly the amount of holiday childcare for school age children.
"What we have found, and we have done surveys across Wales, is that there is a very, very strong link between the amount of childcare and poverty.
"That's a problem because in areas of higher deprivation there is less childcare and that's a vicious circle.
"People find it harder to get jobs because there is no childcare to support them."
It is feared the situation across Wales could be about to get worse as cuts take effect and changes to the benefits system mean more parents are looking for provision, which in some areas is already scarce.
"There has been investment over the last 10 years in Wales but perhaps not to the level needed," added Mr Dallimore.
"But there are things people can do to break down barriers to parents who are nervous about using childcare and there is a lot we can do across agencies to support parents and increase the demand for childcare."
Providing quality, affordable and accessible childcare is a key plank of the assembly government's child poverty strategy and pivotal, they say, in supporting Wales out of the recession.
The assembly government accepts that its 2005 Childcare Strategy is out of date, and has established a new set of priorities, including ensuring that enough childcare provision is secured in every locality to allow all children to access good quality provision, and to enable parents to work.