Liberal Democrat deputy leader Simon Hughes has warned coalition ministers that they will have to change their planned welfare cuts if they are to get them through Parliament.
Mr Hughes said that three of the proposed seven changes to housing benefit set out in Chancellor George Osborne's spending review were the "wrong ones" and would need to be altered if Lib Dem MPs were to support them.
On Sunday, Nick Clegg, the Lib Dem leader and Deputy Prime Minister strongly defended the Government's deficit reduction plan, saying that it was essential to lift the "dead weight of debt" from the economy.
However, the strains within the coalition were again apparent, with fresh rumblings of discontent within the Lib Dem ranks over university tuition fees and funding for disadvantaged schoolchildren.
Mr Hughes said that he and other Lib Dem MPs were making it "loud and clear" to ministers that they would have to re-think the housing benefit plans, which form a key plank of Mr Osborne's £18 billion of welfare cuts.
On Sunday, Mr Hughes said; "I don't think there will be a parliamentary majority in the House of Commons for the current plans - not for all the seven proposals. So I don't think they will go through as they are, and I think Government understands that there has to be negotiations."
