Wealthy pensioners would lose their winter fuel allowance and free TV license under Lib Dem plans the party will confirm as Labour and the Tories continue to battle over which party is pro-business.
The Lib Dems plans will be unveiled hours after experts warned the Conservative's proposed spending cuts could see pensions lowered.
The Liberals will also say they would cut only £4 billion from the welfare bill - £8 billion less than the Tories.
But the party would raise benefits by just 1 per cent a year for two years - in effect a real terms cut.
The Liberals will also say their plans would not require any rise in income tax, national insurance, VAT or Corporation Tax rates.
But aides to Nick Clegg would not be drawn on whether the plans would be "red lines" in any coalition negotiations.
Meanwhile the Institute for Fiscal Studies (IFS) think tank suggested that George Osborne's economic plans could prompt difficult questions over pensions.
Paul Johnson, from the IFS, said that he wouldn't "fall off" his stool if taxes rose after the election.
He added that the planned £12 billion welfare cuts would require "really tough decisions" on issues such as means-testing child benefit or pension reductions.
Meanwhile, Labour continued to firefight allegations that the party is anti-business, opening up a line of attack on Smythson, which employs the Prime Minister's wife Samantha Cameron and which has moved its headquarters to Luxembourg.
Labour received helped from Vince Cable who hit out at the Boots boss who attacked Labour at the weekend.
The Lib Dem Business Secretary said that Stefano Pessina had "lost quite a lot of moral authority once it was discovered he was lecturing political parties from the standpoint of paying his tax in Monaco".
But Labour came under attack from another senior business figure who said that the party's approach "scared" him.
Simon Woodroffe, who founded the Yo! Sushi restaurant chain and is a former Labour supporter, said he was worried about the way Labour targeted business leaders.
Lord Myners, a former Labour minister and one-time chairman of Marks & Spencer, said that Labour was pro-business but needed to "talk in a language that business understands"
In an interview Ed Balls, Labour's shadow chancellor, was unable to name a prominent Labour business backer.
Former CBI director general Lord Jones, another former Labour minister , said Mr Balls' memory lapse was an indication of a "much bigger problem with business".
He said: "It's not about a personal policy about whether you are taxed at 50%, it's not about a mansion tax, it's about this concept that at the moment you are not hearing Ed Miliband or Ed Balls or the others standing up and saying 'creating wealth is a good thing'."
However, Lord Jones said industry liked Labour's approach to the European Union.
Meanwhile Tory Work and Pensions Secretary Iain Duncan Smith claimed that the welfare state was growing at the slowest pace since its creation thanks to the coalition's "reversal of reckless spending".
His comments came after the shadow work and pensions secretary Rachel Reeves warned that Tory economic policies would increase the benefits bill.
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