Millions of people struggle to reach a GP because they are met with an engaged tone when they call their local surgery, it was claimed.
Every month more than six million patients who phone a doctor between 8am and 10am are unable to get through, research suggested.
And it found 93% of calls to surgeries which use normal landlines go unanswered because the number is busy.
Meanwhile, those which used a system to treat calls increased the number of patients getting through first time to more than 98%. These callers found it more than twice as easy to get hold of a doctor and three times as easy to get test results on the phone.
Network Europe Group (NEG), a telephone service provider which conducted the study, is now calling on the Government to adopt a standardised system so people are able to make appointments or pick up test results when they need to.
Dean Rayment, managing director of NEG, said: "We were genuinely shocked by the findings of our research. We think the Government will be equally shocked."
But he said doctors should remain free to decide on the system that works best for their patients.
Questions have been raised over the use of automated systems which previously saw customers charged over the odds to contact their local health service. But recent legislation means patients only pay for the cost of a local call.
The Department of Health stressed GPs should have the freedom to provide services as they see fit.
A spokesman said: "The NHS White Paper published earlier this summer set out plans to give everyone the right to choose the GP that best meets their needs and we are removing ineffective top-down political targets that get in the way of GPs responding to people's needs. Instead of the Government telling GPs what patients want, we want patients to tell their GP themselves what they want and then give GPs the freedom to provide services and be accountable for the results they achieve. We also intend to roll out one single number 111 for all urgent care needs by 2013."