Shelter Scotland director Graeme Brown will visit the Scotland Office to urge Mr Carmichael and the UK Government to exempt homeless people living in temporary accommodation
Shelter’s demands also include making discretionary housing payments to help those struggling with the changes, and provision for advice and advocacy for those affected.
Changes to housing benefit mean social sector tenants who are deemed to have a spare room have seen a reduction in their payments.
Campaigners say the reform has already resulted in increased levels of rent arrears and greater homelessness.
Shelter Scotland says homeless people living in temporary accommodation owned by the local authority are affected by the bedroom tax whereas those living in non-local authority owned accommodation are not.
This hits Scotland “disproportionately hard” as about 50% of temporary accommodation is local authority owned while the majority is also larger in size, the charity says.
Mr Brown said: “That homeless people are being hit with a bedroom tax bill in temporary accommodation they have no choice over is especially callous and will land homeless people with debts when they are already in a vulnerable position.
“That is why we are urging all politicians to act now to help banish the bedroom tax monster from tens of thousands of homes across Scotland.
“The starting point should be to exempt homeless people with no option other than temporary accommodation from the bedroom tax.”