A Tory victory in the General Election will usher in "a massive culture change at every level of government", says leader David Cameron.
He said it would replace Labour's spendaholic administration with a new "government of thrift".
In a keynote speech to the Conservative Spring Forum, Mr Cameron will blast Labour for wasting billions of pounds of taxpayers' cash.
He will also pledge to sack any Tory ministers who fail to "deliver more for less".
In the speech Mr Cameron will say that the election - expected in a year's time - must bring about a "complete change of direction" for Britain after 13 years of Labour rule which have ended in recession and the inauguration of an "age of austerity".
"It is clear now that this will not be any old election," he is expected to say. "It will be one whose outcome will shape Britain for a very long time.
"And it is an election we must win. We must win it because there are deep, dark clouds over our economy, our society and our whole political system.
"Steering our country through this storm and reaching hope on the other side cannot mean sticking to the same, wrong course. We need a complete change of direction - and that's what the election must bring.
"I'm not just talking about changing one group of ministers for another. Or one set of policies, plans and proposals for another. I'm talking about a whole new, never-been-done-before approach to the way this country is run."
Labour's "economic incompetence" has left Britain in its deepest recession since the Second World War, with its highest debt in history, Mr Cameron will say. "Labour are spent. The money has run out. Unless we deal with this debt crisis, we risk becoming the sick man of Europe again."
