The number of workers claiming housing benefit "to make ends meet" will continue to increase if a Conservative government is elected next year, Labour will claim today.
Shadow work and pensions secretary Rachel Reeves will say the number of people in work but also claiming housing benefit is forecast to double from 2010/11 to 2018/19.
She will suggest this forecast will be met if the Tories remain in power and will argue that l ow wages and job insecurity are behind the rise.
Ms Reeves will say House of Commons library analysis shows £12.9 billion extra - or £488 per British household - will be spent between 2011/12 and 2018/19 on providing working people with housing benefit while the number of caseloads increases to 1.238 million in 2018/19 from 617,000 in 2010/11.
Ms Reeves will visit Pudsey in West Yorkshire today, close to her Leeds West constituency, as she attempts to present Labour as the party capable of keeping welfare spending under control and to make work pay while claiming the Tories have failing programmes and rising costs.
The speech is part of a summer offensive ordered by Labour leader Ed Miliband to draw clear lines with the Conservatives in the run-up to next year's general election.
But the Conservatives have insisted the latest messages emerging from Ms Reeves show that Labour has not learnt its lesson on welfare spending and warn that the Opposition's policies will land future generations w ith "more debt than they can ever hope to repay".
Ms Reeves is expected to say today: "The number of working people claiming housing benefit is set to double because the Tory Government has failed to tackle low pay, insecure work and the cost-of-living crisis.
"That's meant thousands more people have been forced to rely on housing benefit to make ends meet.
"Labour will raise the minimum wage, introduce living wage contracts and get 200,000 homes built a year by 2020 to tackle the housing benefit bill and ensure working people can make ends meet."
Ms Reeves is also expected to increase her estimate of the time it will take the Government to fully roll out universal credit, which is a reform aimed at merging a series of benefits into a single payment, from 1,052 years to 1,222 years.
She told the Commons in June that fewer than 6,000 people had been placed on the new benefit, with mo re than seven million claimants due to receive universal credit on current plans.
Work and Pensions Secretary Iain Duncan Smith has insisted the reforms would be delivered by 2017, as announced.
Ms Reeves will say today that there is "no bigger crisis" in Mr Duncan Smith's department than universal credit, reiterating her call for a three-month pause of the programme to allow the National Audit Office to review the scheme.
In response to Ms Reeves, Work and Pensions Minister Mark Harper said: " We inherited an out-of-control housing benefit system from Labour that created a culture of dependency.
"Their system saw some people claiming £104,000 a year of hard-working taxpayers' money to live in expensive areas."
Mr Harper said the coalition's benefit cap had "put an end to unlimited housing benefit".
He went on: "But Labour haven't learnt their lesson.
"They voted against our housing benefit cap, they voted against our overall cap on benefits and they still plan to borrow and spend more by restoring the spare room subsidy - landing future generations with more debt than they can ever hope to repay."
Ministers have insisted that around £6 billion of taxpayers' cash will be saved from May 2010 until the end of the current parliament next year by changes to housing benefit.