Labour's blueprint for tackling the youth unemployment crisis could cost the taxpayer £6billion a year, a report warned on Wednesday.
Former Labour Cabinet minister Alan Milburn will finally publish his plans next week for dealing with the one million 'Neets' who are not in education, employment or training.
The review is central to Andy Burnham's claim the Government can rein in the runaway welfare bill 'in a Labour way'.
But the PM admitted last week the reforms would require 'investment up front'.
The Resolution Foundation suggested on Wednesday the cost of implementing Mr Milburn's plans could top £6billion.
The organisation, known as Labour's favourite think-tank, said the Prime Minister would have to 'show us the money' to achieve results.
Mr Milburn's interim report highlighted figures suggesting the state spends 25 times more on benefits for young people than it does in trying to help them into a job. One study found that ratio is 50 times in some cities, such as Liverpool.
The former Labour health secretary is expected to point to countries such as the Netherlands, Germany and Denmark which spend far more on job support measures and have lower youth unemployment rates.
Former Labour Cabinet minister Alan Milburn (pictured speaking to students in Newcastle in October) will finally publish his plans next on how to deal with the one million 'Neets' not in education, emplloyment or training
The Resolution Foundation on Wednesday said that even matching the Organisation for Economic Co-operation and Development average for spending on work coaches and job subsidies would cost £5billion more.
A further £1billion would be needed to restore funding for further education to 2010 levels, which Mr Milburn is also expected to recommend.
The report said it might be possible to claw back some of the cash by reducing benefit entitlement for some claimants.
Mr Milburn is likely to recommend that funding increases are introduced over time. Government sources said initial funding announced next week is likely to be substantially lower than £6billion.
But Tory welfare spokesman Helen Whately said Mr Milburn appeared to be 'rolling the pitch for spending more money'.
Mr Burnham acknowledged last week the Milburn review would involve upfront costs, but said that 'in time, the savings will come'.
Chancellor John Healey has admitted Labour will not succeed in cutting the welfare bill before the next election, despite mounting concerns about the cost.