The Scottish Government's plans to scrap council tax will mean the loss of hundreds of millions of pounds in benefits, UK ministers have said.
The Scottish Government wants to scrap council tax
The SNP administration's plans had banked on retaining the £400m a year rebate from Westminster.
And Holyrood ministers' aim for a local income tax could not be brought in until 2011, BBC Scotland has learned.
SNP Finance Secretary John Swinney said it was clear the council tax benefits belonged to Scotland.
UK Scottish Secretary Des Browne questioned why the Scottish Government would need to retain the cash if they had found a "fairer" alternative to council tax.
He told BBC Scotland's Politics Show: "If you have a benefit that is paid to an individual to balance the effects of their inability to be able to pay tax and that tax is taken away, then the benefit has to go as well."
A spokesman for Mr Swinney said: "The council tax benefit is Scotland's money, plain and simple.
"It is part and parcel of the system of locally raised tax to help fund local government services, and of course, the money should be retained in Scotland."
Meanwhile, it emerged that the earliest that local income tax could replace council tax would be just before the next Holyrood election, according to a senior government source.
The Scottish Government - which provided funding for a council tax freeze across the country - is soon to publish its consultation on the local income tax.
The Liberal Democrats support the change, but disagree with the SNP over some of the detail of the policy.
And there is still not enough support in the Scottish Parliament to push it through.