Nearly one-third of patients are unable to book appointments more than two days in advance, a survey reveals.
GPs have to see patients within 48 hours under government targets
The Healthcare Commission asked 117,000 patients for their views of dental, GP and local health services.
Most were satisfied, but 30% complained about advanced access - an issue the government has promised to tackle.
During the election campaign, Tony Blair was put on the spot on BBC One's Question Time by patients unable to book appointments in advance.
Members of the audience told him they could only book appointments within 48 hours because of government targets.
Doctors have said they can only offer limited appointments in advance as they have to keep slots free to meet the two-day target.
At the time he pledged to investigate the issue and take action if necessary, although Department of Health officials insisted it was not a widespread problem.
But the findings of the Healthcare Commission suggest the 48-hour target has been having negative consequences.
The survey also showed 12% of patients were not being seen within two working days - again at odds with government figures showing only a small fraction were.
Access to dental services was also criticised. Some 43% of people said they were not registered with a dentist, despite two thirds wanting to be.
But the NHS performed much better on satisfaction ratings. Three-quarters said they had confidence in their doctor and dentist.
And a fifth of GP patients said they were not given any information about side effects of medication.
Healthcare Commission chief executive Anna Walker said the survey gave an "invaluable insight" into what patients think about the care they receive.
Diana Church, the mother who harangued the prime minister on Question Time, said the survey reflected the problems she had had trying to get an appointment for her son.
And she said found it "surprising" the government had, until recently, claimed nearly all patients could book in advance.
The Department of Health accepted the findings over access were at odds with their own records, pointing out they gathered evidence from practices.
It said that, in the future, more emphasis would be given to patient surveys, while the public would be asked what sort of guarantee they wanted on advanced bookings as part of the White Paper consultation.
Health Minister Lord Warner said: "It is unacceptable that some practices are still not allowing patients to book an advance appointment with a GP."
But Dr Hamish Meldrum, chairman of the GPs committee, said: "This is trying to fix the problem without sorting out the underlying cause. With a shortage of GPs there is bound to be a pressure on appointments."
And Shadow Health Secretary Andrew Lansley added: "The 48-hour target does not make it easier to see a doctor.
"On the contrary, it reduces a GP's flexibility to manage patient demand and creates a no-win situation."