In official notes from a meeting on 1 December last year, DWP advisers revealed they were not intending to put a time limit on the work experience placements.
When asked at the meeting if there was a maximum duration to the placements, the reply was: "There are no plans to introduce a maximum time limit."
Neil Bateman of the National Association of Welfare Rights Advisers said: "This proposal is very worrying. There are completely inadequate legal and medical safeguards – bearing in mind that these are people with long-term health problems and disabilities, often serious ones.
"Compulsory, unpaid work may worsen some people's health, with the consequences of the DWP's savings being passed on to the NHS at greater cost.
"If jobs are there to be done, people should get the rate for the job, instead of being part of a growing, publicly funded, unpaid workforce which, apart from being immoral, actually destroys paid jobs."
"When Conservative backbench MP Philip Davies suggested [last year that] disabled people should work for less than the national minimum wage, he was castigated, but it now appears to be government policy."