Conservative and Lib Dem ministers have "banged" the table at a cabinet meeting to mark the impending passing of the NHS reforms into law, No 10 has said.
The Health and Social Care Bill, for England, has had a difficult passage through Parliament but was finally passed by the House of Lords on Monday.
The government hopes it will now get Royal Assent and enter law by Easter.
MPs are now taking part in an emergency Labour debate which calls for the bill's progress to be delayed.
The motion says MPs should not consider planned NHS changes for a final time before an assessment of the potential risks to the health service is published.
Afterwards, MPs will consider the amendments to the bill agreed by the Lords on Tuesday.
The legislation would abolish Strategic Health Authorities and Primary Care Trusts and give much greater control over care budgets and commissioning decisions to GPs and other health professionals.
"We will continue to campaign hard to try and mitigate the worst excesses of this bill”Dave Prentis Unison
The bill has been the subject of a prolonged battle over the past year - with professional bodies representing doctors, nurses and other NHS workers resisting the changes.
There has also been criticism from several leading Liberal Democrats of Conservative Health Secretary Andrew Lansley's plans.
But the prime minister's spokesman said there had been "cross-party banging" of the table at cabinet to mark the imminent Royal Assent for the legislation.
He added that it would become law before the Easter Recess, which starts next Tuesday.
But unions said they would not relent in their opposition to the bill once it becomes law.
"We will continue to campaign hard to try and mitigate the worst excesses of this bill," said Unison general secretary Dave Prentis, adding that ministers were ignoring the "groundswell of opposition" to the proposals.
"Patients will have a two-tier health service and where they live will determine the healthcare they receive."
Members of Unison, which represents more than a million public sector workers, held a minute's silence outside Parliament in protest at the changes.