The Government has launched its "revolutionary" Work Programme, pledging to support around two-and-a-half million people back to work in the next five years.
Employment minister Chris Grayling said the scheme is the biggest single payment by results employment programme ever introduced in this country, replacing much of the existing support on offer.
But the Work Foundation research group warned in a report that the programme would do little to improve job prospects for people living in economically weaker areas of the UK.
More than 500 voluntary sector groups will be involved in delivering the programme, including Mencap, the Citizens Advice Bureau, the Prince's Trust and Action for Blind People. Ministers said that under the Work Programme, providers would be free to design support, based on the needs of jobseekers and local labour markets.
Mr Grayling said: "The Work Programme will tackle the endemic worklessness that has blighted so many of the country's communities for decades. It is revolutionary in the way it tailors support to jobseekers' individual needs and pays organisations primarily for getting people into sustained employment.
"We want to establish a deal where we will do our bit and get people ready for work and in exchange we will expect people to take up the work that is available. We are sending out a clear message - if you can work, and we can help you find a job, you must work.
"Millions of people on out-of-work benefits who have previously been shunted from dole queue to training room to dole queue again will now finally be able to access support that's built around their needs."
Mr Grayling said providers will be paid for supporting people into employment and helping them stay there for longer than ever before, with higher payments for supporting the hardest to help.
Over the course of the seven years the contracts will run, the total value is likely to be between £3 billion and £5 billion.
The Work Programme replaces employment support currently on offer including the New Deals, Employment Zones and Pathways to Work, with ministers saying they were "overly prescriptive" and failed to achieve enough good job outcomes for the long-term unemployed or good value for money for the taxpayer.