The work and pensions secretary has pledged to protect disabled children who will be hit by the bedroom tax.

Speaking in the House of Commons today, Iain Duncan Smith said he would publish guidance tomorrow for local authorities on how to effectively use discretionary housing payments, which are designed to mitigate against the impacts of welfare reform.

He said it was a ‘matter for the local authority to decide’ in cases where families say they need an extra room, but that there was sufficient money available to protect those who need it.

Under the bedroom tax, which comes into effect from 1 April, working-age social tenants who receive housing benefit will have their payments cut if they are deemed to have one or more spare bedrooms.

‘The guidance coming out tomorrow will make it clear that we will apply judicious judgement across the board where there’s a disabled child,’ he told MPs.

‘These spare rooms will be kept for those who need them, but with so many houses with spare rooms and so many needing housing we will not go on subsidising it.’

He also accused Labour politicians of scaremongering by falsely representing who would be affected by the penalty.

Amidst continuing Labour opposition to welfare reform, Mr Duncan Smith said the overall benefit cap is ‘absolutely right’ and has public support.

Last week prime minister David Cameron said families with severely disabled children would be exempt from the under-occupation penalty. Critics have said this is incorrect, and accused the prime minister of not knowing the detail of the policy.

Conservative Party chairman Grant Shapps was quizzed on the subject on BBC Radio Four’s You and Yours programme, and confirmed it was up to local authorities to decide how to use discretionary housing payments to support disabled children.