Pat McFadden has backed a legal guarantee of employment support for young people while confirming that some younger benefit claimants will receive less when they undergo scheduled reassessments.

The work and pensions secretary said assistance needed a “legislative underpinning” because the present offer was “vague”. His intervention comes ahead of Alan Milburn’s review, due on Tuesday, which will recommend guaranteed job placements or training for under-25s.

Milburn, a former Labour cabinet minister, wants billions diverted from benefits into employment support over the next decade. His report is expected to recommend ending under-25s’ eligibility for the health element of UK-wide Universal Credit and for Personal Independence Payment, the main disability benefit in England and Wales. Some could receive a new “additional cost allowance” for everyday expenses arising from health conditions.

McFadden confirmed that younger claimants would move to a new benefits system at reassessment, with some receiving less than under current entitlements. Others, including people with long-term disabilities, would receive more, he said.

Milburn’s proposed bargain is reduced benefit entitlement for some alongside a government duty to offer apprenticeships, college places, coaching or a job. He argued that temporary schemes, including Kickstart during the pandemic, had been less effective at reducing long-term joblessness.

But the practical meaning of a legal guarantee remains unsettled. McFadden said it would need careful drafting. Councils already have specific duties on matters including homelessness and child protection; central government duties tend to be broader, such as providing a comprehensive health service.

Shadow work and pensions secretary Helen Whately backed lower welfare spending but rejected the guarantee. She argued that cutting employer taxes and business regulation would create “real jobs”, calling it “absurd” to raise employer taxes to “subsidise things that look like jobs”.

Benefit reductions could also revive Labour opposition: MPs defeated an earlier benefits-cutting plan under Sir Keir Starmer last year. Milburn warned that sustainable savings could not be achieved within two or three years and that “crude cuts” would create other government costs.

He also said GPs should not sign people off as unable to work and urged ministers to reconsider Labour’s manifesto pledge to phase out the lower minimum wage for 18-to-21-year-olds, arguing that moves towards it had imposed substantial business costs.

Separately, from next April, eligible jobless under-25s will be offered subsidised six-month minimum-wage jobs after 12 months of unsuccessful job-searching, rather than 18. This is the scheme’s second eligibility expansion, after its maximum age rose from 21 to 24 earlier this year. The wider question remains what specific support the proposed legal duty would entitle each young person to receive.