Work and Pensions Secretary Iain Duncan Smith won't take part in the planned Labour debate on the "bedroom tax" later today.

The welfare reform - which the government refers to as the "spare room subsidy" - is the subject of an Opposition Day debate in the House of Commons.

The Secretary of State in charge of the policy however will not be there to defend it.

Read: Iain Duncan Smith not attending 'bedroom tax' debate

The Shadow Work and Pensions Secretary Rachel Reeves is expecting to debate the issue with a more junior minister from the government department.

A number of protestors are planning to travel to Westminster ahead of the debate and Labour sources suggest the Work and Pensions Secretary is "running scared".

Labour is forcing a vote in the Commons on a motion calling on the government to repeal the controversial policy.

Rachel Reeves claims the welfare change hits 660,000 housing benefit claimants with an average loss in payments of £720 per year.

The Labour motion reads:

That this House regrets the pernicious effect on vulnerable and in many cases disabled people of deductions being made from Housing Benefit paid to working age tenants in the social housing sector deemed to have an excess number of bedrooms in their homes; calls on the government to end these deductions with immediate effect; furthermore calls for any cost of ending them to be covered by reversing tax cuts which will benefit the wealthiest and promote avoidance, and addressing the tax loss from disguised employment in construction; and further calls on the government to use the funding set aside for Discretionary Housing Payments to deal with under-occupation by funding local authorities so that they are better able to help people with the cost of moving to suitable accommodation.

Update: The Department for Work and Pensions has told ITV News Mr Duncan Smith had written to Rachel Reeves to tell her he would not be at the debate as he is at the International Conference on Youth Employmenton the Prime Minister's behalf, along with 20 heads of state including Angela Merkel and Francois Hollande.

Watch: Tenants urge minister to think again about 'bedroom tax'

*Watch: Tenants urge minister to think again about 'bedroom tax' *