Government policy has created an austerity generation, threatening to send one million more children into poverty, a new report warns.
Research revealed that families already at greater risk of poverty, such as lone parents and those with a disability, will suffer the most from cuts to their income.
The report said cuts to Universal Credit will put one million more children into poverty, warning that the long-term impact of austerity policies will be felt for years to come.
The promise of greater rewards from work made to working families has been "broken" because of cuts to Universal Credit and tax credits, said the Child Poverty Action Group (CPAG) and the Institute for Public Policy Research (IPPR).
Losses for working families from cuts in the tax credit system average £930 a year and £420 a year from cuts to Universal Credit, the analysis found.
A full-time working couple on the national living wage would have to work 17 extra days a year to make up losses caused by cuts in work allowances, said the report.
Alison Garnham, chief executive of the CPAG, said the report was "straightforward and shaming".
She added: "Since 2010, rather than investing in our children, government policy has been creating an austerity generation whose childhoods and life chances will be scarred by a decade of political decisions to stop protecting their living standards.
"The promise of increased rewards from work made to families with children under the new Universal Credit benefit has been broken. The Universal Credit we see today is not the Universal Credit that was sold to everyone a few years ago.
"Even after taking into account increases in the minimum wage, rising tax allowances and extra childcare help, working families will be the biggest losers from cuts made to the benefit system.
"Cuts to Universal Credit have substantially reduced the rewards from work for many families. If the Government's flagship anti-poverty measure ends up rolling out poverty then it's hard not to see that as a colossal failure of public policy."
The group said this month's Budget was an opportunity for the Chancellor to mount a "full-scale rescue mission" for Universal Credit.
A Department for Work and Pensions spokeswoman said: "We're committed to supporting families and there are now 200,000 fewer children living in poverty than in 2010. This report assumes that people won't take any steps to improve their lives, which we know is untrue. Unlike the old system, Universal Credit (UC) rewards those working more hours.
"Evidence shows that UC claimants look to take on more hours than they did under JSA (Jobseeker's allowance), and for the first time they get personalised support to help them progress in work."