The number of children growing up in poverty in working households is set to be a million higher than in 2010, according to a new study.
Research for the TUC estimates that 3.1 million children with working parents will be below the official breadline this year.
The report suggests that around 600,000 children with working parents have been "pushed" into poverty because of the Government's benefit cuts and public sector pay restrictions.
TUC general secretary Frances O'Grady said: "Child poverty in working households has shot up since 2010.
"Years of falling incomes and benefit cuts have had a terrible human cost. Millions of parents are struggling to feed and clothe their kids.
"The Government is in denial about how many working families just can't make ends meet."
A Government spokeswoman said: "We do not recognise the TUC's figures. The reality is there are now one million fewer people living in absolute poverty compared with 2010, including 300,000 fewer children.
"We want every child to get the very best chances in life. We know the best route out of poverty is through work, which is why it's really encouraging that both the employment rate and household incomes have never been higher."
Margaret Greenwood, shadow work and pensions secretary, said: "These shocking findings show just how damaging eight years of austerity has been for working families."