Ministers are due to publish welfare proposals on Monday
Claimants "will have to work to get their benefits" under proposals due out on Monday, Work and Pensions Secretary James Purnell has told the BBC.
Help would be offered to find work, he said, but responsibility was "vital".
He added that the plans in the Welfare Green Paper for England and Wales - including abolition of the incapacity benefit system - were "revolutionary".
Tory leader David Cameron claimed the government had taken up ideas recently proposed by his party.
He promised the government the support of Conservative MPs to get the measures in the Welfare Green Paper through Parliament if they faced a rebellion by Labour backbenchers.
Speaking on the BBC's Andrew Marr Show, Mr Purnell said the proposals would put responsibility "right at the heart of the welfare state" and "transform lives".
The worst thing about the old system was, people were given no help at all... to improve their health, to get back to work, to improve their confidence
The draft paper - to be published on Monday - said there could be "no right to a life on benefits" for anyone capable of working.
Mr Purnell said he welcomed Tory support because it meant doing "the right thing for the country", but said the Conservatives were placing the emphasis on responsibility without providing any support.
On incapacity benefit he said the old payments would be scrapped, claimants reassessed and a "completely different benefit" introduced.
"The worst thing about the old system was, people were given no help at all. They weren't given help to improve their health, to get back to work, to improve their confidence.
"We will make sure for the first time that everybody gets that help. And one of the revolutionary things that happen is that we will be using the benefits that we would have spent if people had stayed on the benefit... to get them back into health and back into work."
He said the government wanted to get one million people off incapacity benefit by 2015.
In February government welfare adviser David Freud suggested less than a third of the 2.7m people claiming the benefit were doing so legitimately.
The work and pensions secretary on welfare reforms
A draft of the Green Paper, which was leaked on Friday, said ministers were also proposing a "work for dole" scheme, requiring people to do "full-time activities" to benefit themselves and their community.
It said everyone other than severely disabled people, carers and parents of young children should be expected to look and train for work.
People who do not take up the offer of support would lose benefits, said Mr Purnell.
Giving his response to the Green Paper, Mr Cameron said: "Great - the government has taken up our ideas. I am absolutely thrilled at that.
"What (Mr Purnell) has done is very much taken the ideas we came up with in January, that are very clearly thought through and involve tough choices."
Mr Purnell said he "completely disagreed" that the proposals would be unpopular with some Labour colleagues.
"I think that people who see the way incapacity benefit or drug addiction or deep unemployment can scar communities are desperate to turn that round and when I speak to my colleagues they want a system that provides support for people, but also responsibility."
The government had already announced plans to make young people who have been out of school, training or a job for six months to do at least four weeks' "work-related activity".
The document suggests extending that to the long-term unemployed and says while it has yet to consult on how the schemes would work, they would involve "individuals engaging in a variety of full-time activities of value to themselves, their community and prospective employers."
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