Working parents in the UK "simply do not earn enough" to escape poverty and the government should raise the national minimum wage to help them, the social mobility tsar Alan Milburn argued.
A report authored by the Social Mobility and Child Poverty Commission, which is chaired by the former Labour Health secretary, found that two-thirds of Britain's poor children are now in households where an adult works.
"Child poverty is overwhelmingly a problem facing working families, not the workless or the work-shy," the commission warned.
The report said the goal of ending child poverty by 2020 is likely to be missed by two million children partly because of low wages and falling living standards.
The commission argued that the National Minimum Wage of £6.31 ($10.17, €7.44) per hour is now worth £1,000 less in real terms than it was in 2008 and 4.8 million workers, often women, earn less than the Living Wage of £8.55 an hour in London and £7.45 an hour in the rest of the UK.
"Too often, the working poor are the forgotten people of Britain," the body stressed.
The commission urged the government to raise the national minimum wage, incentivise Jobcentre Plus and pay Work Programme providers for the earnings people receive not "just for getting people into work" and reallocate Budget 2013 childcare funding from higher rate taxpayers to help those on Universal Credit meet more of their childcare costs, among other things.
The group also called on employers to more actively "step up to the plate" by providing higher minimum levels of pay and better career prospects in a way that is "consistent with growing levels of employment".
"Just as the UK government has focused on reducing the country's financial deficit it now needs to redouble its efforts to reduce our country's fairness deficit," Milburn said.
He added: "If Britain is to avoid being a country where all too often birth determines fate we have to do far more to create more of a level playing field of opportunity. That has to become core business for our nation."
The report follows the news that Britain's jobless rate remained stable at 7.7%, but there were 18,000 more people working than there were from March to May 2013.