Health unions say the government's efforts to give patients more choice could have the opposite effect.
Each year 9.4m referrals for non-emergency treatment are made
A radical shake-up of the NHS in England means patients are able to choose between at least four hospitals for non-emergency operations.
Ministers say the Patient Choice reforms will cut waiting times and drive up standards of care.
But union leaders fear it could force unpopular hospitals to close and that patients could make wrong choices.
The director of nursing at the Royal College of Nursing, Alison Kitson, said nurses advocated the principle of choice but in reality GPs had insufficient time to research the information required for patients to make the right choices.
And unpopular hospitals could eventually be forced to close, she said.
"There is a real danger that creating a market within the NHS could effectively erode choice for patients as the most popular hospitals become overwhelmed, while the least popular sit empty and may eventually face closure.
"Fewer hospitals mean less choice for patients - and it is the most vulnerable members of society, such as the elderly, who will suffer the most if they cannot access hospital services on their doorstep, leaving them with no real choice at all."
Some GPs have also expressed concerns.
Dr Eric Rose, whose practice is in Milton Keynes, said: "What I would like is for my patients to be seen more quickly at the local hospital.
"If I am going to give them a choice of other hospitals, I want a lot more clinical information.
"They're not going to a Kwik-Fit centre to have a piece bolted on or removed. They are patients that need care."
Patients' groups have welcomed the reform in principle but say it risks being undermined by delays in upgrading the NHS IT system to link GP practices to hospitals.
The booking system is currently available in only 25% of GP surgeries and in these cases, the traditional route of making appointments by letter will have to be used.
Full implementation of e-booking, which was intended to tie-in with Patient Choice, has been delayed by a year, and the Conservatives say such problems with the system are undermining choice.
However, Health Secretary Patricia Hewitt said despite the delays, patients would still see the benefits.
"Choice is now a reality in the NHS. Patients have new rights over their own healthcare.
"These rights will allow patients to choose services which best meet their individual needs and preferences.
"It will take some time for everybody to get used to this new system, but I am confident that the benefits will be worth it."
In pilot schemes, most people offered the choice took it, while those that stayed with their local hospital benefited from shorter waiting times, Ms Hewitt added.
Booklets have been produced for each local area detailing the choice on offer for each speciality.
For some, patients will have a choice of as many as 10 hospitals, including private hospitals where care can be provided at NHS cost.
The government is planning to extend the initiative so that by 2008 patients can choose from any hospital.
It will form part of a wider plan to extend choice across the NHS, including in primary care settings such as GP surgeries.
A white paper later this month is expected to set out how that can be achieved.