Ed Miliband will reveal that each of Labour's general election commitments will require no extra borrowing when he launches the party's manifesto in Manchester today.
Miliband will also announce that the first line a Labour government's first Budget would be that it "cuts the deficit every year".
"The very start of our manifesto is different to previous elections. It does not do what most manifestos do. It isn't a shopping list of spending policies," he will say.
"It does something different: its very first page sets out a vow to protect our nation's finances; a clear commitment that every policy in this manifesto is paid for without a single penny of extra borrowing."
The pledge is a clear bid for Labour to sure-up their economic credentials, an area where the Conservatives have been campaigning heavily.
The Conservative Treasury minister David Gauke, in response to the news, claimed Miliband has "no plan to clear deficit and balance the book".
"Even Miliband's own campaign chief admits Labour will borrow more to pay for their unfunded spending promises," Gauke argue.
"Everybody knows the SNP will call the tune and force even more borrowing, even more debt and even more taxes on a weak Miliband government. Britain's hardworking taxpayers will pay the price for the economic chaos."
Elsewhere, Nick Clegg accused Miliband and the shadow chancellor Ed Balls of planning to play "Russian roulette" with the UK's economy.
"By not naming a date to balance the books Labour are not coming clean with the British people about what their plans mean," the Liberal Democrat leader said.
"We know Labour don't have the courage to apologise for crashing the economy but they should have the bravery to name a date and show they have learnt their lessons.
"Labour's economic house of cards has already collapsed once this century – the Liberal Democrats will not let it happen again."
The manifesto launch comes just 24 days before the election on 7 May, with Labour three points ahead of the Tories (36% vs 33%) in the latest opinion poll from YouGov.
The survey, conducted between 11 and 12 April, also put Ukip on 13%, the Liberal Democrats on 7% and the Greens on 5%.