HOUSING associations in ­Scotland can expect a bill of almost £80 mil-lion over three years as tenants hit by the so-called bedroom tax are left with no option but to downsize, a new report claims.

The 160 organisations face lost rent, tenancy changes as ­thousands of tenants look to move to smaller properties, the cost of staff training and a publicity effort to ensure residents know about the changes, warns the ­Scottish Federation of Housing Associations (SFHA).

Also known as the spare room subsidy and introduced in April last year by the UK Government, reduced rates of housing benefit are paid to social tenants deemed to be occupying homes larger than they need.

The SFHA has urged the Scottish Government to do more to ­mitigate the policy's impact.

In today's report, the SFHA claims the policy will cost Scotland's associations a combined total of £79.1m. It says social landlords have not been able to plan for these costs, and the money could have paid for 800 new social homes. The organisation says it is only now that the true impact on ­landlords is ­becoming apparent.

The report, entitled The Real Cost of the Bedroom Tax for Scottish Housing Associations and Co-operatives, bases its estimates on the frontline experience of members. It said 36,000 housing ­association tenants and 47,000 council tenants will be affected by the spare room subsidy.

It breaks this down into tenancy management costs covering expenses such as the reallocation of homes as thousands of tenants look to downsize, unpaid rental income and legal costs which it says will amount to at least £55,264,800 over the first three years of the policy.

Communications such as advice provision, tenant surveys and newsletters were costed at £9,250,000. System changes such as staff training and updating policy, procedures and IT systems are expected to cost £14,592,800.

Maureen Watson, SFHA head of policy, said the extra cost has not been built into the business plans of its members. She said: "This will drive up rents for all tenants and increase the housing benefit bill for the UK Government.

"The SFHA is strongly opposed to the bedroom tax. We are continuing to make representations to the UK Government, seeking to have this unfair and incompetent policy repealed."

With the policy unlikely to be withdrawn, she called for a long-term plan to protect the interests of current and future tenants.

She warned: "It is not simply about the lost revenue arising from rent arrears, but also all of the associated additional costs incurred by social landlords while seeking to support their tenants as best they can."

The report came as the Scottish Government revealed £15.4m of Discretionary Housing Payments (DHP) were made between April and November last year to help 45,000 households in Scotland affected by housing benefit cuts under the bedroom tax.

Scottish ministers earlier made an additional £20m available to help councils mitigate the impact of the DWP's spare room subsidy.

Graeme Brown, director of ­Shelter Scotland, said: "It is good news that more than £15m has been distributed by local ­authorities in Scotland to help 45,000 households struggling with their rent as a result of welfare reform - in particular the bedroom tax. This means that more than £18m pounds of the total discretionary housing payment pot is still available to help people pay their rent."

A Department for Work and Pensions spokesman said: "We have given councils in Scotland over £13m in 2013/14 to support vulnerable people who need extra help as we fix the benefits system, but it's simply not affordable to pay housing benefit for people to have spare rooms."

He added that councils have had plenty of time to prepare for this policy.