The Government plans to reassess all 3.2 million claimants on disability living allowance, which it is scrapping.
Ministers aim to cut 20% from its budget when it replaces the allowance with the Personal Independence Payment.
Parts of the benefit, such as help for those with mobility problems living in care homes, are expected to be ended entirely.
Papworth Trust chief Adrian Bagg said: “Their daily costs are typically 25% higher than the non-disabled’s. For example, some have to use more expensive accessible taxis to leave their home.” Labour shadow minister for the disabled Margaret Curran said: “The changes risk denying people a more independent life. Removing the mobility component for those in residential care, could trap them in their own homes.”