The British Medical Association (BMA) has warned against a "slash and burn" effect saying a radical government health shake-up in the UK which would introduce more competition for services could damage the future of the Nation Health Service.
An increasingly market-based approach to healthcare would create "waste, bureaucracy and inefficiency" and shift the focus onto cost over quality, the BMA said.
Government proposals set out in July would give GPs control over Ģ80 billion of the NHS budget, while scrapping two tiers of managers.
The BMA acknowledged there were positive elements of the government's plans, such as devolving more control to patients and frontline clinicians, but said other aspects would "undermine the stability and long-term future of the NHS".
Publishing its response to the "Equity and Excellence:Liberating the NHS" White Paper today, the union said that cuts being imposed on the NHS to create savings of 15 to 20 billion pounds would make changes on the scale outlined "very challenging".
The union also voiced "serious concerns" about plans for all trusts to have foundation status by 2013-14 and warned against "changing the ethos" of NHS provision.
Dr Hamish Meldrum, chairman of council at the BMA, which represents doctors and medical students, said: ?There are proposals in the White Paper that doctors can support and want to work with.
"But there is also much that would be potentially damaging.
"The BMA has consistently argued that clinicians should have more autonomy to shape services for their patients, but pitting them against each other in a market-based system creates waste, bureaucracy and inefficiency."
In a strong statement to British Health Secretary Andrew Lansley, the BMA adds: "We urge the government and NHS organisations to focus on those areas where they can truly eliminate waste and achieve genuine efficiency savings rather than adopt a slash-and-burn approach to health care, with arbitrary cuts and poorly considered policies."
Consultation on the plans will end later this month, after which ministers are expected to start formal talks with BMA negotiators about implementing the changes.
Lansley played down the criticisms, saying the plans would lead to better health care for patients.
"There are many GPs across the country who are keen to make the transition quickly, others want to know more about how it's going to work before they implement it," he said.
"This is what the consultation process is about, everyone coming forward to say how can we make this work."