Deputy Prime Minister has "knocked on the head" claims he supports the cutting of £10bn from benefits after the next general election.
Chancellor George Osborne this week announced a further £10bn cuts at the Conservative Party conference.
But Mr Clegg - who was reported to have agreed to the move - said wealthier people needed to pay more before benefits were cut.
He was speaking to an audience of BBC Radio 5 live listeners.
At the Conservative conference in Birmingham this week the chancellor claimed a further £16bn of savings must be found by 2015/16 to meet his target of balancing the budget within five years.
This, he said, would include cutting £10bn more from the welfare bill by 2016-17, on top of the £18bn announced in 2010.
Asked about the prospect of further cuts, Mr Clegg said: "The idea that of that £16bn we're just going to scoop out £10bn from welfare - which will inevitably hit the poorest before asking anything of the wealthiest - no. Flatly no."
The country needed to carry on "tightening its belt" for some time into the future, Mr Clegg said, but those at the top should be asked to contribute first.
"I start from a very simple principle that when we're all having to make sacrifices... you ask people at the top and then you work down.
"You don't ask people at the bottom and then work up."
He continued: "I think it's unrealistic to assume that you can't make any more savings from welfare... but it hasn't been agreed in government.
"I certainly don't agree with this idea that you just pluck a £10bn figure out of the sky and say 'that's what we're going to do' without asking how you can do that more fairly."
During his conference speech Mr Osborne said the better off would pay more in taxes, but the budget could not be balanced "on the wallets of the rich".
Mr Clegg vowed to veto the £10bn cuts plan at his own party conference the previous week, but there were reports he had agreed to proposal, provided it was balanced by a bigger contribution from the rich.
Mr Osborne ruled out Lib Dem proposals for a levy on high value properties, the so-called mansion tax, or a new wealth tax, saying they would harm enterprise.
Mr Clegg received a rough ride from the 5 live listeners, many of whom were his constituents, who accused him of going back on his word over student tuition fees.
The Lib Dem leader confirmed that he would be standing for re-election in Sheffield Hallam at the 2015 general election.