Half a million people are set to lose their disability benefits under government plans.
Work and Pensions Secretary Iain Duncan Smith said he was determined to introduce radical reforms to disability allowances which could slash the annual cost by £2.24 billion.
Around 500,000 people in the UK who receive disability living allowance (DLA) could no longer be eligible for the replacement personal independence payment (PIP) under the plans, which are outlined in a report by the Department for Work and Pensions this month.
In an interview with the Daily Telegraph, Mr Duncan Smith said there had been a 30% rise in the the number of claimants in recent years, with the annual cost of the benefits soon to reach £13 billion.
Under the reforms, two million claimants would reassessed in the next four years and only those considered to be in need of support able to qualify.
Mr Duncan Smith told the Daily Telegraph said: "We are creating a new benefit, because the last benefit grew by something like 30% in the past few years. It's been rising well ahead of any other gauge you might make about illness, sickness, disability or for that matter, general trends in society.
"A lot of that is down to the way the benefit was structured so that it was very loosely defined. Second thing was that in the assessment, lots of people weren't actually seen. Third problem was lifetime awards. Something like 70% had lifetime awards, (which) meant that once they got it you never looked at them again. They were just allowed to fester."
Mr Duncan Smith defended the reforms which could see people without limbs, including ex-servicemen and women, no longer entitled to disability benefits as their everyday mobility is not undermined by their prosthetic limbs.
He told the Daily Telegraph: "It's not like incapacity benefit, it's not a statement of sickness. It is a gauge of your capability. In other words, 'Do you need care, do you need support to get around?'. Those are the two things that are measured. Not, 'You have lost a limb'."
Ministers are consulting on the new eligibility criteria for the disability benefit system which will be announced in the autumn.