Around 160,000 disabled people will be stripped of benefits entitlements after the Government shifted the goalposts to deal with legal rulings, according to Labour.
A tribunal said personal independence payments (PIP) claimants with psychological problems who cannot travel without help must be treated like those who are blind.
Claimants who need support to take medication should be assessed the same way as those managing therapies like dialysis at home, it also ordered.
Penny Mordaunt insisted urgent reforms were needed following the upper tribunal rulings and said she would not be referring them for review to a specialist committee.
The disabilities minister said she was reforming the payments to "restore the original aim of the benefit" to make sure the most needy were given support.
Ms Mordaunt said no claimants would see a reduction in the amount of PIP previously awarded by the Department for Work and Pensions (DWP).
But Labour said the Government's equality assessment showed how 160,000 would miss out on money that was "rightfully" theirs.
Debbie Abrahams, shadow work and pensions secretary, said: "Instead of listening to the court's criticisms of personal independence payment assessments and correcting these injustices, the Government has instead decided to undermine the legal basis of the rulings.
"This is an unprecedented attempt to subvert an independent tribunal judgment by a government with contempt for judicial process.
"By shifting the goalposts, the Tory government will strip entitlements from over 160,000 disabled people, money which the courts believe is rightfully theirs.
"This is a step too far, even for this Tory government. Labour will stand with disabled people, who have already borne the brunt of seven years of austerity, in fighting this injustice."
PIP is extra money awarded to help people with everyday life if they have an illness, disability or mental health condition.
Mrs Mordaunt said: "Two recent upper tribunal judgments have broadened the way the PIP assessment criteria should be interpreted, going beyond the original intention.
"In order to make sure the initial purpose of PIP is maintained, we are making drafting amendments to the criteria which provide greater clarity.
"This will not result in any claimants seeing a reduction in the amount of PIP previously awarded by DWP."