Participants will have to go to the job centre every day, some will be offered community work placements and others will receive intensive coaching.
Those who fail to take part could lose jobless benefits for four weeks.
Work and Pensions Secretary Iain Duncan Smith said: “Everyone with the ability to work should be given the support and opportunity to do so.
“The previous system wrote too many people off, which was a huge waste of potential for those individuals as well as for their families and the country as a whole.”
The programme was first outlined by Chancellor George Osborne at last year’s Conservative Party conference.
Labour says that the government has mis-diagnosed the problem.
Stephen Timms, shadow employment minister, said: “Under David Cameron’s government nearly one in 10 people claiming Job Seeker’s Allowance lack basic literacy skills and many more are unable to do simple maths or send an email.
“A Labour government will introduce a basic skills test to assess all new claimants for Job Seeker’s Allowance within six weeks of claiming benefits.”
BBC social affairs correspondent Michael Buchanan said the government had signed up more than 70 organisations to provide work experience under the scheme.
However, our correspondent added that the Salvation Army is not taking part, because it believes if someone has not found a job after two years of intensive support, their lack of work experience is not their only barrier to employment.
Also on Monday, those wanting to claim Jobseeker’s Allowance will have to prove they are ready for work, before they can apply.
The government has said the changes will help to put an end to the “one-way street in benefits”.
But the TUC says the rules could discourage more people from claiming it.
“Making the JSA rules tougher and tougher will put people off claiming the benefits they need without doing much to help them get jobs,” said Frances O’Grady, the TUC’s general secretary.
But the Department for Work and Pensions (DWP) said there was no evidence that people would be put off claiming.