Citizen's Advice has criticised George Osborne's targeting of sickness benefits in a summer spending review aimed at cutting the £155bn deficit.
Lizzie Iron, Citizens Advice Head of Welfare Policy, says that moving high numbers or people from Employment and Support Allowance (ESA) onto Job seeker's Allowance was worrying as people could end up losing out on support they should receive to return to the workplace.
Speaking at the G20 summit in Toronto today, Osborne identified incapacity benefit and its successor, employment and support allowance, as areas for savings.
He said: "We have got to look at all these things, make sure it protects those in genuine need, protects those with disabilities and protects those who can't work but also encourages those who can work into work. That is the purpose behind our welfare reform."
He adds that Over 2.5m people are on incapacity benefit or employment support allowance - costing about £12.5bn a year.
Iron notes that, while many people who have been out of work for a long time do want to work they can face a number of barriers, both from their limited capacity to work and from poor attitudes and practices of many employers.
She says: "One third of employers say that they deliberately exclude people with a history of long-term sickness or incapacity (including people with disabilities) when recruiting staff, according to the CIPD. People need to be confident that when they are too ill or disabled to work or unable to find work because of their sickness or disability that there is a safety net."