Many GPs are snubbing a flagship government scheme aimed at making the NHS more efficient, a survey suggests.
The aim of the scheme is to reduce hospital admissions
From April, GPs can take control of their budgets from primary care trusts (PCTs) and commission services.
Ministers believe the move will lead to fewer hospital admissions as GPs will be more responsive to patient needs.
The NHS Alliance found only 25% of 601 GPs polled had signed up and over 50% would not, but health officials said the level of interest was pleasing.
The alliance, which represents PCTs, said its survey found a further 18% planned to join the practice-based commissioning scheme in the future.
The BBC understands just a handful of areas have the majority of their practices on board, rendering many of the benefits impossible.
Under the system, GPs will be allowed to keep the savings they make on their budgets to spend on services as they see fit.
The government believes this incentive will allow more specialist services to be set up than under PCTs, which as larger bodies would seem better placed to oversee such services.
But without mass participation across an area, GPs will struggle to fund some of the more innovative schemes.
Setting up the sort of services that will ultimately lead to reductions in hospital admissions, such as specialist GP-led clinics to target specific diseases, costs vast sums of money and requires co-ordination among practices.
A combination of GPs' lack of enthusiasm and PCT reluctance to hand over budgets they have only had control of for a few years are being blamed for the slow take up.
One GP, who is taking part, told BBC News: "I can understand the reluctance. There has been so much change in the last few years, doctors are unsure how long this initiative is going to last so many are reluctant to dive in.
"Time is also being taken up implementing the new GP contract, so this is perhaps too much for many.
"But without lots of GPs on board in one area, it will be very hard to achieve some of the things the government wants."
NHS Alliance chairman Dr Michael Dixon agreed.
"At this stage, not that many are on board and that will obviously affect how much can be achieved," he said.
"I think some PCTs are forward-thinking, but others have been reluctant to hand over control."
The British Medical Association, which is in favour of the scheme, blamed the government's delay in issuing advice - the technical guidance was sent out only a month ago.
"The technical guidance was published only very recently and was scarce on detail, so, for many, questions still remain unanswered," it said.
The government wants to see all GPs running their own budgets by 2008.
A spokesman for the Department of Health said it was pleased with the numbers of doctors who had expressed an interest.
"We have always said that GPs should be able to develop practice-based commissioning at their own pace," he said.
"That is why we have made practice-based commissioning voluntary for practices."