Hundreds of thousands of people cannot book GP appointments because none are available, or struggle to get through to their surgery on the phone, according to a new survey.
A poll of 1.93 million people found 21% said it was not easy to get through on the phone to their GP surgery.
Some 265,844 thought it was not very easy, while a further 132,618 said it was "not at all" easy.
Some 38% (732,888) said it was fairly easy and while 31% (596,669) thought it was very easy.
Asked how simple it was to speak to a doctor on the phone, 19% thought it was not at all or not very easy, 25% thought it was very or fairly easy, 44% had not tried and another 12% did not know.
The poll covers GP practices in England and was carried out between January and December 2010 for the Department of Health.
Of the 1.1 million people who had tried to see a doctor fairly quickly in the previous six months, 79% had been able to do so.
But one in five (20% or 221,608) could not, with 83% of those (184,495) saying a reason was there were no appointments available.
Health Secretary Andrew Lansley said: "Patients rightly have a strong sense of confidence and trust in their GPs, but GPs have not previously had the freedom to respond to patient needs appropriately.
"Instead of government telling GPs what patients want, our modernisation plans will free GPs to make services more responsive to patients.
"GPs will be empowered to ensure patients get the care they need, when they need it, including out-of-hours care.
"We will also introduce the new, free-to-call, NHS 111 service which will provide easy access to urgent care services, including access to out-of-hours services."
Jo Webber, Deputy Policy Director of the NHS Confederation, said: "Patients need to be able to access their GP easily, otherwise there is a serious risk they will add to the already considerable pressures faced by A&E departments and 999 services.
"This survey shows more needs to be done to ensure consistent access."