A charity has found that majority of men are unaware of a blood test described as the "first line of defence" against the disease.
The Prostate Cancer Charity is worried that men are effectively being denied access to the prostate specific antigen (PSA) test.
Under current NHS guidelines, men over the age of 50 have the right to ask for a PSA test if they have had a balanced discussion with their doctor about its benefits and drawbacks.
But according to the Telegraph, the charity found that a tenth of GPs "do not support this right", while a fifth "never talk about the PSA test with at-risk groups," said a spokesman.
He said that most GPs considered access to the test as a "major hurdle".
Experts are divided about the test, which gives many false positive and false negative results.
One of the reasons is that levels naturally vary widely between men. A raised level can also indicate an enlarged prostate, rather than cancer, or cancer that is growing so slowly that it is unlikely to cause any problems.
Despite the shortcomings, the charity says it is currently the "first line of defence" for picking up potential problems.
John Neate, chief executive of The Prostate Cancer Charity, said: "The lack of knowledge by so many men about the PSA test, reinforced by our latest research, is a completely unacceptable inequality in our society and can no longer be tolerated.
"GPs must begin to engage men much more pro-actively in discussions about prostate cancer, their risk of the disease and the role of the PSA test. They must never stand in the way of a man's right to make a personal, informed choice about having the test."