More than 20,000 children in Scotland would be affected if housing benefit for the under-25s was removed, the Scottish government has claimed.
UK Chancellor George Osborne has said taking the benefit away could contribute to multi-billion savings needed in the welfare budget.
Deputy First Minister Nicola Sturgeon called the plans "seriously misguided".
However, the UK government said benefit changes were returning "fairness" to the system.
In a speech last week, Mr Osborne set out £25bn of further public spending cuts, including £12bn from the welfare budget.
He said more austerity lay ahead, as the job was "not even half done", and suggested making welfare savings by cutting housing benefit for under-25s and restricting council housing for those earning more than £65,000 a year.
The Scottish government published its own analysis of figures from the Department of Work and Pensions, and claimed there were 20,059 children in the 32,700 households in Scotland who would be affected if the benefit was withdrawn.
Ms Sturgeon said: "My main concern is the risk that this cut would pose to the 20,000 children who would need to be re-housed and would face the prospect of being made homeless."
The Holyrood politician has requested a meeting with UK Work and Pensions Secretary Iain Duncan Smith to discuss the proposals.
She added: "We have seen that when decisions on Scotland's welfare system are taken in Westminster they have negative impacts on our people and families. That is why we want decisions about things that affect Scottish people taken in Scotland - by people who live and work here.
"We want a welfare system based on the clear principles of fairness and dignity that fosters a climate of social solidarity."
Mr Osborne's speech highlighted rifts with his coalition partners the Liberal Democrats, with Deputy Prime Minister and Lib Dem leader Nick Clegg accusing the Conservatives of wanting to make "cuts for cuts' sake".
Labour's UK shadow chancellor, Ed Balls, said Mr Osborne was being "forced to make more cuts is because his failure on growth and living standards has led to his failure to balance the books by 2015".
The Scottish government set up the Expert Working Group on Welfare in January 2013 to look at the costs and delivery of welfare should there be a "yes" vote in this year's independence referendum.
Scottish ministers want the power to reverse existing housing benefit changes such as the under-occupancy penalty, a reduction of housing benefit for social tenants deemed to have surplus rooms, which UK ministers call a "spare-room subsidy" and opponents have dubbed the "bedroom tax".
A spokeswoman for the UK Department of Work and Pensions said: "Removing the spare room subsidy returns fairness back to the system - when in Scotland alone there are 158,000 on housing waiting lists and 25,000 living in overcrowded homes."
The Liberal Democrats said a housing benefit cut for the under-25s was "not coalition government policy".
A spokeswoman added: "The Lib Dems want a stronger economy and a fairer society. Yes, we have to balance the books but we won't do that on the backs of the poor.
"The Scottish government have failed to outline the difficult decisions they will need to make under independence."