The charity Barnardo's has warned that nearly one in three of Welsh children are living in poverty.
One worker for the charity said children in Wales occasionally go without food or heating.
Its research found numbers had fallen from 33% to 28% in the last five years, but was 2% lower than the UK average.
The UK Government has pledged to eradicate child poverty by 2020, and last year the assembly government also set out targets to tackle it.
On Wednesday Barnardo,s said the UK Government was not on target to meet its pledge, and called on both governments to "redouble" their efforts.
Barnardo's has called for cheaper childcare to help working families
Child poverty is generally assessed by whether the family's income is less than 60% of the UK's average.
Sally Jenkins, a project manager from Barnardo's said children living in poverty may sometimes go without food.
"There will be times where something happens and there is no-one else to call on and on occasion some of those children and those young people will go hungry," she said.
Despite the fall in the number of children living in poverty, the charity says Wales has seen an increase in the proportion of working households living below the poverty line.
It has called for more affordable childcare to help the country's poorest families, as many parents are faced with low wages and high childcare costs.
Barnardo's Cymru Director Raymond Ciborowski, said: "Most parents we work with want to work and there should be a focus on work as the best route out of poverty.
"But for many with low skills or qualifications getting a job means moving from workless poverty to working poverty."
One of the parents supported by the charity is 16-year-old Hannah Erickson from Cardiff, who has an 11-month-old baby called Dylan.
After paying all her bills, she is left with around £10 a week to cover clothes for herself and her baby, bus fares and other essentials.
During the winter, Hannah said she did not have enough money to heat her flat.
"Because it was so cold I had to put £20 a week in the gas, and it ran out, so I went without gas for three days," she said.
"It made me feel very, very bad because I couldn't provide the gas for him (Dylan) when he needed it," she said.
Hannah would like to train to become a hair and beauty therapist at college, but says the cost of childcare is one of the things stopping her.
"I don't think anyone wants to be in this situation, everyone wants the best for their kids," she said.
"I'm doing the best I can for him, but not what I would like to do for him, take him places, buy him what he needs, what I would like him to have."