Doctors have accused ministers of rushing legislation that could allow changes to local hospitals to be forced through without proper consideration of patients' needs.
The British Medical Association (BMA) called on Health Secretary Jeremy Hunt to backtrack on plans to give greater powers to a trust special administrator (TSA).
The changes form part of the Care Bill, which faces its first test in the Commons today, and follow the legal battle over the future of Lewisham Hospital in south-east London.
Ministers were defeated in the High Court over their attempt to cut A&E and maternity services at the hospital and had an appeal rejected in October.
The courts ruled the special administrator brought in to deal with problems at the neighbouring South London Healthcare NHS Trust did not have the power to suggest changes at other trusts.
But under amendments added to the Care Bill in the House of Lords, the BMA said TSAs will be empowered to also make changes in neighbouring trusts without consulting patients, clinicians, or the public.
Ministers have said the change is a clarification of the present policy but the BMA warned it would allow the Health Secretary to "force changes through the back door".
Dr Mark Porter, chair of the BMA Council, said: "With the NHS under financial strain there is immense pressure to make changes to the way services are delivered.
"We need a full debate on the best model for providing sustainable, high quality services, taking on board the views of clinicians, politicians and, crucially, the public.
"Most importantly any reconfiguration of services must be evidence-based and clinician-led, and not motivated by financial or political pressures. By rushing through these changes the Government is paving the way for current and future health secretaries to force changes through the back door without taking into consideration clinical or local needs.
"As we saw with Lewisham Hospital any attempt to use the failure of a hospital to force through change at neighbouring trusts can result in unnecessary strain on services, patient uncertainty and a huge cost to the taxpayer.
"It is vital that NHS reform is clinically, not politically, driven and we call on the Government to either amend the clause to ensure full consultation of all those affected is safeguarded, or remove it entirely."
Trade union Unite's head of health Rachael Maskell said: "What Jeremy Hunt is attempting to do is to achieve by a parliamentary sleight of hand what he failed to do through the courts.
"It is clear that the health secretary is hijacking the Care Bill by tacking on this clause which has no relevance to the rest of the bill.
"It shows scant respect to parliamentary traditions and this country's judicial process built up over many centuries. Parliament should be in tune with judicial decisions, not trying to overturn them."
The legislation is mainly aimed at reforming the care system, placing a cap on the costs faced by the elderly and putting in place a system to prevent people being forced to sell their homes to pay care bills.
But Age UK warned there were a number of "myths" about the changes, which follow a review of the care system led by Sir Andrew Dilnot.
Caroline Abrahams, charity director at Age UK, said: "The good news is the Care Bill updates and improves the law and the new 'Dilnot system' removes the fear of endlessly spiralling care bills, but the bad news is the cap on care costs isn't nearly as straightforward as it sounds and there's a lot of 'devil in the detail' with the funding reforms.
"Unfortunately, the small print generally makes the new system less generous than originally hoped and fewer older people stand to gain as a result.
"Though it can still be improved, the Care Bill is fundamentally good legislation, but it won't make much practical difference without the funding to bring it to life. At the moment we fear the reforms will be underfunded, but it is not too late for the Government to act.
"Ensuring older and disabled people get the care they need is what really matters."