Most GPs are not convinced the planned shake-up of the NHS in England will benefit patients, a BBC poll suggests.
The survey of 827 doctors by ComRes found less than a quarter agreed putting GPs in charge of budgets would lead to a noticeable improvement for patients.
It comes after leading health unions have criticised the pace and scale of the changes over the past week.
Patient groups said ministers must now work to get health staff on board.
Under the proposals set out in a white paper in July, GP consortiums are to be created to take on responsibility for managing local services by 2013. The 10 strategic health authorities and 151 primary care trusts are to be scrapped in the process.
But the plans have caused unease among health professionals.
The British Medical Association, Royal College of Nursing, Royal College of GPs and Unison have all expressed concerns in their responses to the official consultation, which ends later this month.
The unions warned the changes may threaten the efficiency savings the NHS is having to make, while some are worried about what they see as the increasing commercialisation of the health service.
The BMA has also said the changes could threaten the traditional doctor-patient relationship.
The BBC survey was carried out online between 23 and 30 September.
It found 25% said they would be willing to take on the extra responsibility of planning and buying health care for their local populations with 57% saying they would not and 18% expressing no opinion.
However, under the plan the government will not need every GP to become involved in management and so having a quarter wanting to do it could suffice.
A majority also felt they were not well prepared to become involved in commissioning care in the following areas - cancer, emergency hospital care, mental health and paediatrics.
However, some of these areas may end up being the direct responsibility of the independent national board.
Meanwhile, seven in 10 said they thought the changes would lead to a greater role for the private sector.
While it could be argued there is still plenty of time to train and prepare doctors, it is the fact that so many GPs are struggling to see how the overhaul will benefit patients that has caused most concern.
Only 23% said it would benefit patients with 45% saying it would not and 32% expressing no opinion.
Katherine Murphy, of the Patients Association, said while she had some concerns about the white paper plans, they also had the potential to benefit patients by empowering them to get more involved in their care.
On the poll results, she said: "It is worrying. We need GPs on board for this to work. If they are apathetic we should not go ahead with it, but there is time to deal with the concerns being raised. The government needs to do this."
Professor Steve Field, president of the Royal College of GPs, said having a quarter willing to take on responsibility for commissioning was "not worrying".
But he added: "One of the challenges for the Department of Health is that they now have to go out and talk and work with GPs to get them to better understand how they can influence care."
A Department of Health spokesperson said: "The questions asked in this survey are misleading about the government's policy proposals. We are not asking GPs individually to take on commissioning responsibility.
"However, if a quarter of GPs are prepared to take on the extra responsibility, it's a powerful indication of the existing willingness to implement our reforms.
"With two and a half years with which to learn from pathfinder commissioning consortia and establish shadow arrangements, there is ample time for practices that do not yet feel ready to build capability collectively. We intend to put in place support arrangements to help practices develop capability."