The government hopes to cut the number of people on incapacity benefit by introducing a new tougher test.
The tests could cut the number of claimants by 20,000
It aims to end "sick-note Britain" with the assessments, which could see the number of annual claimants fall by 20,000.
But people who receive the benefit have contacted the BBC News website to argue that the government's clampdown is unfair.
One such person says he is desperate to get back to work, but has found it impossible to get a job.
David Le Compte, 51, has been on incapacity benefit since he broke his leg in three places, two years ago.
'Less than useless'
Before the accident he was a truck driver and tried to get back to work after being signed off.
"I tried straightaway to get back to work, to do something light. The moment I did I was hounded by the Department of Work and Pensions who wanted to take me to court because I had earned four pence over what I was allowed.
"They made such a fuss that the agency who was giving me the work wouldn't touch me with a barge pole."
Mr Le Compte, from Thetford in Norfolk, says he was then sent to an interview, where he was asked what he would like to do as he could no longer drive trucks.
After saying he could perhaps work in an office he was sent details of truck driver jobs in Scotland, Leeds and Manchester.
Following another interview he was sent information sheets on how to become a truck driver.
"I have found the DWP and job centres less than useless, they're non existent. They do nothing," he said.
"I have been so inactive for the past two years that my condition has got worse, because I have been unable to get a job."
Mr Le Compte said he has applied for 110 jobs but because he has been unemployed and on incapacity benefit for two years, no one will employ him.
"I have been for another medical and have been signed off for another two years, but all I have is £80 a week - you can't live on that.
"When ministers talk about 'sick note Britain' I don't think they know what they are talking about."
Dr David Blowers worked as an assessor on the appeal panels for more than two years and says the test system does not work.
"I have seen people getting benefit who frankly shouldn't have received it and others who were not getting it who were frankly so sick it was a surprise they had come in.
"We have to find a way to help the people who want to work, introducing a new test like this is not the way.
"Many people with a disability are saying they would like to work and this is not possible, these are the people who would be disadvantaged by any new test. This is unconscionable to me."
There are now one million fewer people on benefits and numbers on incapacity benefit are falling for the first time in decades, a spokesman for the Department of Work and Pensions said.
The government will be providing people with a more tailored approach to giving them the skills they need to get jobs, he added.
"We want to give people exactly the help that will make them able to compete for jobs whether it be more skills or building up their confidence for example. This approach will help more people off benefits and into work."