The Conservatives have pledged to save £2.8bn a year by ending Disability Living Allowance (DLA) payments to families of children with "milder cases" of behavioural disorders, learning difficulties or ADHD.
The policy is one of a series of measures which the party says will save £36bn from the welfare budget.
Shadow work and pensions secretary Helen Whately said the system risked putting children on a "conveyor belt" towards a "lifetime on benefits".
Labour described the Tories' plan as a "charter for homelessness and human misery that would push people into hardship and end up costing the state more".
DLA for children allows parents to claim between £30.30 and £194.60 per week to help cover the additional costs that come with raising a disabled child.
The child must either have difficulty getting about or need more looking after than a child of the same age who does not have a disability.
The Conservatives say child DLA is the "fastest growing benefit in the UK's welfare system", citing government statistics showing the number of cases had risen from 521,476 in 2020 to 914,000.
The party is proposing that in cases where a claim is for a behavioural disorder, learning difficulty or ADHD, only those with the highest need will be eligible for cash payments.
