Practice-based commissioning (PBC) has failed to deliver real benefits to patients since it was introduced three years ago, experts have said.
Progress in implementing the policy has been "painfully slow" and, in some areas, has stalled completely, according to the King's Fund think tank.
The government health reform has also delivered little in terms of financial savings for the NHS, it added.
Under the policy, GPs are allowed to run local budgets and "buy in" services such as hospital and community care, but the report has found that very few GPs are using the scheme to commission new services.
The study found that GPs needed more support from PCTs to fully implement the policy and often lacked the skills to use practice-based commissioning properly.
It also noted concerns over possible conflicts of interest between the role of GPs as both providers and commissioners of services.
Report coauthor Nick Goodwin said: "PBC has the potential to deliver better services for patients and financial savings for the NHS, but progress has been painfully slow over the past three years.
"The NHS must harness what remains of the limited enthusiasm of GPs and commit to a fundamental redesign of the policy if it's to live up to its potential."