A committee of MPs may be about to launch an inquiry into NHS job losses and hospital closures.
Is the NHS in a critical condition?
The government has come under fire as thousands of NHS jobs have been lost across the country.
Tony Blair admits the NHS reforms have reached a "crunch point", but remains determined to press ahead.
Liberal Democrat MP Paul Burstow, a member of the Commons health committee, said it was time to question ministers on the issue.
And last month Labour MP Kevin Barron, the committee chairman, warned trust budget deficits were "clearly threatening to destabilise" the health service.
More than 7,000 job cuts have been announced across the NHS in recent weeks, as trusts struggle to balance their books.
It is thought the service in England will end the financial year with a deficit in excess of £600m.
Scale of the problem
Ministers argue that only a small proportion of trusts are in financial difficulties, and that the projected deficit is only around 1% of the total NHS budget.
But some trusts are angry that they face cuts despite balancing their books, in order to bail out others who are in deficit.
Mr Blair told an audience of senior health workers on Monday that the NHS faced a very tough challenge, but he said reform was vital to ensure the service was more responsive to patients.
Mr Burstow said the committee had not yet signed off on the terms of reference for an inquiry.
But he said: "Members of all parties on the committee are concerned that the government keep telling us this is a localised problem, not a national problem.
"We want to find out whether that is really true, or whether the scale of the problem is in fact greater, and is one that needs action to deal with it across the country."
Mr Burstow said the NHS appeared to be in "perpetual revolution" and blighted by instability.