A report from the Commons' work and pensions committee finds ministers are unlikely to meet their target of halving child poverty by 2010.
When the pledge was made in 1999, 3.4 million were living in poverty. Since then this number has fallen by 600,000 but this means the 1.6 million figure expected by 2010 is expected to be missed by around one million.
Call for investment
Today's report calls for heavy investment to demonstrate the government's ongoing commitment to the pledge in chancellor Alistair Darling's first Budget next week. It also says more should be done to ensure those who are working are significantly better-off than those receiving benefits.
Committee chairman Terry Rooney warned there would remain a core of parents who are the hardest to help, which may affect the government's ultimate aim of eradicating child poverty altogether by 2020.
"We believe [the government] needs a long-term strategy on benefit income for those who are unable to work," he said.
Campaign groups echoed the report's calls for renewed investment. Child Poverty Action Group chief executive Kate Green said£4bn was needed and called for "moral courage" to ensure the money is spent wisely.
Work and pensions secretary James Purnell insisted the government's child priority targets remained a "key priority".
"We have done a lot, but there is still more to do," he commented.