Health secretary Andy Burnham has accused his Conservative counterpart of inventing spending plans "live on air".
Burnham told the BBC that in setting out plans to continue spending more money on healthcare, shadow health secretary Andrew Lansley had announced a new Tory policy.
But he warned that a decision to spend more money on the NHS would mean "major cuts" in the budgets for other government departments.
Speaking earlier on BBC Radio 4's Today programme, Lansley explained that his party intended "real terms growth for the NHS" beyond 2011.
"We are going to maintain real terms growth in expenditure in the NHS," he said.
"We have to do this otherwise the demands on the NHS of rising technology and increasing demographic and the number of people getting older would make our ability to improve services to amongst the best in the world impossible.
"Unfortunately what this means is that there have got to be very powerful spending constraints across government."
Lansley added that international aid and education spending would also increase, but said that would mean "over three years after 2011, a 10 per cent reduction in the departmental expenditure limits for other departments".
Burnham responded that the Conservatives would cut government spending overall if they were elected into power.
"[Lansley] seemed to me to be writing the Tory spending plans live on air on your programme," Burnham told the BBC.
"He was saying that they would spend more on healthcare, which is a new thing. I have not heard them say that before.
"If they are going to spend more in a period that David Cameron has always said will be about austerity for the Conservative Party, cuts in public spending, we really are looking at major cuts in the budgets of other departments."
Both frontbenchers were appearing on the BBC to discuss a NHS Confederation report which warns that the health service is facing its biggest organisational and financial challenge ever and will not survive unless it changes.
The report warns that in just under two years, the NHS will face the "most severe constriction ever" in its finances.
It called for action now to ensure that the NHS remains true to its founding principles and continues to provide care for free at the point of need.
Speaking ahead of the NHS Confederation's annual conference in Liverpool, head of policy Nigel Edwards warned that health staff have to be prepared for spending to fall in real terms by up to three per cent by 2011.
"We had seven years of plenty," he said. "Now it looks like seven years of famine from 2011 onwards.
"We are really going to have to think very deeply and carefully about everything that we do."

Dods Parliamentary Communications Ltd