The shadow chancellor says the Tories will talk honestly about spending cuts
Shadow Chancellor George Osborne has called for politicians of all parties to have the "honesty" to admit there would be reductions in public spending.
Writing in the Times, Mr Osborne says it is "ridiculous to pretend there won't be cuts" in the future.
He says both the Tories and Labour should have the confidence to tell the public the UK faces a "debt crisis".
But Schools Secretary Ed Balls said the Tories wanted "swingeing spending cuts" so they could cut taxes for the few.
Last week, Tory health spokesman Andrew Lansley appeared to suggest that, in order to protect spending on the NHS and schools, a future Conservative government would cut expenditure in other areas by a total of 10% between 2011 and 2015.
The Conservatives said he had been working from Labour's own figures from the last Budget but the prime minister accused the Tories of planning "savage" public spending cuts.
In his article, Mr Osborne admits that in the past the Tories have "fought shy of using the 'c' word - cuts".
He writes: "We've all been tip-toeing around one of those discredited Gordon Brown dividing lines for too long. The real dividing line is not 'cut versus investment', but honesty versus dishonesty.
"We should have the confidence to tell the public the truth that Britain faces a debt crisis; that existing plans show that real spending will have to be cut, whoever is elected."
He added: "The bills of rising unemployment and the huge interest costs of a soaring national debt mean that many government departments will face budget cuts.
"These are statements of fact and to deny them invites ridicule."
In an article for the Guardian, Ed Balls says the recent Labour leadership quarrels are allowing the Tory plans to escape proper scrutiny.
Speaking on Radio 5 Live, Mr Balls admitted there would need to be "tough choices" and "more efficiency" after the next general election, but insisted that spending cuts to key services were not inevitable.
Mr Balls added: "George Osborne should be honest and clear about the spending cuts he is promising to the British people.
"If we get the economy right, as I believe we are doing, I think we can see the spending on schools and hospitals rising in real terms after 2011."
Liam Byrne, the chief secretary to the Treasury, said the Conservatives were ideologically committed to cutting spending - insisting that regardless of economic circumstances, the Tories would make cuts of £5bn in the present financial year, and of 10% from 2011 onwards.
However, Mr Byrne would not say what Labour intended to do, telling a press conference that Labour intended to increase public spending by 0.7% after 2011.
But Mr Byrne added: "From 2011 onwards we have to decide closer to the time how to divide up the growth in current spending."
Shadow Schools Secretary Michael Gove told BBC Radio 4's The World At One that Mr Byrne's comments were at variance with Mr Balls' remarks that there would be a real-terms increase in education spending under Labour.
"If you ring-fence health spending, and for that matter international development spending, then that means you cannot give a guarantee that you will ring-fence other departments," Mr Gove added.
"Either party doesn't know the position that it's going to be in a month, two months, three months out."