Hundreds of thousands of people will be affected by changes to disability benefits payments in the next five years, the Government has admitted.
The changes will make it harder for many people with disabilities and long-term conditions to qualify for the Personal Independence Payments (PIP) in future, a charity has warned.
But the Government, which said 640,000 people will be affected by 2020/21, said changes will ensure the system is fairer as money goes to those who need it most.
The Department of Work and Pensions (DWP) said a review of cases revealed that a "significant number" of people are likely to be receiving the benefit even though they have "minimal to no ongoing daily living extra costs".
Health professionals carrying out the reviews found that in almost all of the cases it looked at people were being awarded points for aids and appliances that were either already found in the home or could be provided free or at a low cost, the DWP said.
PIP replaced Disability Living Allowance and is designed to help people with the extra cost of disability.
The DWP launched a consultation on a range of options to change how scores are calculated to assess how much people should be entitled to.
Disability Rights UK welcomed the fact that four of the five options put forward were not introduced, but said the final option, to reduce from January next year the points awarded to people who need aids and appliances for dressing and managing toilet needs, will make it more difficult for some.
In a statement on its website the charity said: "Halving the point value of 'aids and appliances' descriptors make it harder for many disabled people and people with long-term conditions to qualify for PIP in future. The Government's own response confirms that this will affect around 640,000 people by 2021."
The organisation said the current PIP assessment fails to consider the extra costs for housebound people who will have higher heating bills, or those with incontinence who will have bigger water bills due to washing their clothes more often.
It said: "We would like to see an assessment which accurately reflect these additional costs.
"However, the current system represents a significant improvement over all of the suggested options in the consultation. PIP needs change, but PIP does not need this change."
Justin Tomlinson, Minister for Disabled People, said: "The introduction of Personal Independence Payment to replace the outdated Disability Living Allowance for working age claimants has been a hugely positive reform.
"But it is clear that the assessment criteria for aids and appliances are not working as planned. Many people are eligible for a weekly award despite having minimal to no extra costs and judicial decisions have expanded the criteria for aids and appliances to include items we would expect people to have in their homes already.
"We consulted widely to find the best approach. And this new change will ensure that PIP is fairer and targets support at those who need it most."