The long-term unemployed would carry out 30 hours of community work over six months under plans to be tested in four areas.
David Cameron said the proposal would help people “get back in touch with the world of work” and would give people skills.
If rolled out across the country the proposal could affect nearly 70,000 people.
Mr Cameron said: “If you go through the work programme but still don’t find work, then we are actually going to be asking people to go through a community work programme where they work 30 hours a week for 26 weeks to contribute to their community.
“That will help many people to get back in touch with the world of work, the idea of having a job, the skills that you need that will give them further help in order to get back into work.”
The proposal is the latest measure to be unveiled by the Government in an attempt to coax people back into work.
It would apply to people who have still not managed to find employment even after support from the Government’s Work Programme, which is designed to offer help to get them a job and is designed to send a “clear message” that those who refuse to engage will not be entitled to financial support from the State.
But critics are likely to question its introduction at a time when unemployment is rising.
Employment Minister Chris Grayling said: “If people who are fit for employment, still haven’t managed to find a job after the intensive support provided by the Work Programme, we want them to do community work and get into the habit and routine of work. “