As figures show an extra 300,000 children living in households that cannot afford to keep their house warm, Labour accuses Osborne of ignoring the issue

Britain's independent spending watchdog should monitor the government's progress in tackling child poverty, Labour has said as new figures showed that progress has stalled under the coalition.

As the figures showed that an extra 300,000 children are living in households that cannot afford to keep their house warm, Labour accused George Osborne of ignoring the issue.

Catherine McKinnell, shadow economic secretary to the Treasury, wants the Office for Budget Responsibility to make a twice-yearly assessment of progress on tackling child poverty in the same way as it makes economic growth forecasts. The OBR assessment would be published before the budget and the autumn statement, forcing the chancellor to take account of it in his "red book", which forms the basis for fiscal policy.

McKinnell, who pointed out that Osborne has made no mention of child poverty in his last three budget speeches, said: "The progress Labour made in reducing child poverty has ground to a halt under the Tories and independent forecasts say it is set to rise. This isn't good enough.

"The Office for Budget Responsibility should be required to monitor and report on the government's progress on reducing child poverty. This should include analysing the impact of budget decisions on the level of child poverty."

The last Labour government introduced a law which committed the government to eradicate child poverty by 2020, a target which is unlikely to be met. Progress on the target is assessed by the social mobility and child poverty commission.

Labour, which has been calling for the OBR to be allowed to assess its fiscal plans ahead of the general election, made the call after new figures showed no change in relative child poverty before housing costs in 2012-13. If it is measured after housing costs then the child poverty level rose by 100,000.

A Labour analysis of Households Below Average Income (HBAI) statistics show that a couple with two children aged five and 14 are worse off on average by £2,132 a year in real terms since 2009-10. The figures also show that between 2009-10 and 2012-13 a total of 1.7 million children – an increase of 300,000 – are living in families that cannot afford to keep the house warm. An extra 400,000 children are living in families that cannot afford to save £10 a month.

McKinnell said: "George Osborne hasn't made a single mention of child poverty in his last three budget speeches. Boosting the role of the OBR to monitor child poverty would make it more difficult for governments and chancellors to ignore the problem and the impact of their choices.

"Labour's plan to deal with the cost-of-living crisis will tackle child poverty and make work pay as we balance the books in a fairer way. We will expand free childcare, freeze energy bills, increase the minimum wage, incentivise the living wage, scrap the bedroom tax and get more homes built."