A Liberal Democrat government would increase taxes on the better-off, big businesses and banks to levy £8bn and end austerity in three years.
Nick Clegg, speaking alongside Treasury Chief Secretary Danny Alexander, also said his party would sign up to £16bn ($24bn, €21bn) worth of spending cuts.
"The coalition plan that we agreed in 2010 was rooted in a long standing Liberal belief that a fairer society is built on the foundations of a sound economy – a belief which goes back to the days of Gladstone," Clegg said.
"But it is clear that the Conservatives no longer see it that way. They see austerity as an end in itself."
He added: "As George Osborne announced at the Conservative Party conference last autumn, they now see deep cuts to public services not as an economic necessity but as an ideological opportunity to shrink the state.
"The Conservatives' so-called long term plan is more like a Tea Party manifesto for Britain."
Clegg also backed £12bn in government departmental spending cuts and £4bn in welfare cuts by 2017/18.
The remaining £14bn needed to achieve a deficit surplus would be raised through £8bn in tax hikes and £6bn by clamping down on tax avoidance.
The speech followed a poll from Survation for Unite, which found that the Liberal Democrat leader could lose his Sheffield Hallam seat at the general election to Labour's candidate Oliver Coppard.
David Cameron blasted the Liberal Democrat economic plan because it involved "substantial" tax hikes.
"I don't think it's right to have a plan that involves really quite substantial tax increases that would hit hard working people," Cameron said.
"The election will come down to a choice between our plan and the chaos that a Labour government with Ed Miliband and Ed Balls at the Treasury would represent."