Britain's hospital doctors want the coalition's controversial NHS shakeup to be scrapped, with many fearing it will lead to health services being privatised, a poll has revealed.

Almost seven in 10 members of the Royal College of Physicians (RCP), which represents hospital doctors, want the health and social care bill withdrawn.

The findings of the RCP's poll of its members' views on the bill are another blow to ministers' efforts to convince doctors their plans are right, and are a significant addition to the medical community's almost unanimous opposition to it.

The RCP polled its 25,417 fellows and members. Of those, 8,878 responded (35%). The survey followed the college's recent extraordinary general meeting to decide its stance on the bill, after some members said it was not being robust enough in its opposition.

When asked for their personal views of the bill, 69% (6,092) said they rejected it as it stood; only 6% (525) accepted it; 22% (1,971) said they "neither completely accept nor completely reject it"; and the other 3% (290) did not offer an opinion.

Of the 8,878 responders, 49% (4,386) said they wanted the RCP to "seek withdrawal of the bill", while slightly fewer – 46% (4,099) – said it should "continue to engage critically on further improving the bill". The other 4% (393) did not offer a view either way.

A third question, asking RCP fellows and members what their main concerns were related to the bill and the wider health agenda, showed that large numbers of hospital doctors fear it will have a negative impact.

Concern about possible privatisation of the NHS, and the planned extension of competition between healthcare providers and choice for patients, loomed large, though many are also worried about the effect of handing control of £60bn of patient treatment budgets from April 2013 to local groups of GPs called clinical commissioning groups (CCGs). CCGs will exercise considerable power, including over the commissioning of services for patients from hospitals.

The RCP members' top concerns about the bill were: 1.Training, education and research (5,550 put in their top five concerns)

2. Use of the private sector (5,414)

3. Commissioning by clinical commissioning groups (4,905)

4. Choice and competition (4,866)

5. Proposed structural change (introducing the new NHS national commissioning board, CCGs, etc) (4,687)

6. Role of secretary of state (3,216)

The poll also found widespread unease about issues already facing the NHS at the frontline, including the quality of patient care, budget cuts, staff shortages and patients not getting continuous care.

"We believe that this is the single biggest survey among the medical royal colleges, with the highest turnout, and while it shows there is a clear majority of the RCP's fellows and members who would personally reject the bill, opinion is divided almost equally on whether the RCP should continue to critically engage or now call for the withdrawal of the bill," said Sir Richard Thompson, the RCP's president.

"The areas of most concern to RCP fellows and members are the areas on which we have been strongly lobbying government, MPs, peers and other stakeholders: training, education and research; use of the private sector; commissioning by clinical commissioning groups; and choice and competition," he added.

The Department of Health played down the importance of the poll, pointing out that the doctors wanting the bill scrapped represented just 17% of the RCP's membership.

"While it is disappointing that some members of the Royal College of Physicians have voted to reject the bill, it is worth noting that only a third of the college's 25,000 members voted in this process, and under half of those members have asked for it to be withdrawn," said Lord Howe, the health minister in the House of Lords.

"We have already strengthened the health bill following the listening exercise and have responded directly to the points raised by the Royal College of Physicians, including making clear that competition would only be used to benefit patients, never as an end in itself.

"We welcome the fact that thousands of doctors have called on their college to continue to engage with the government on its plans for improving the health service. We have committed to working closely with the medical royal colleges on our plans on education and training, which they have welcomed," he said.