HIV tests must be easily accessible in "GPs surgeries and other community settings" as a means of combating the rising number of people who do not know they have the disease, according to a group of experts.
The coalition sent a letter to the government to mark World Aids Day, describing the level of undiagnosed HIV as "a huge public health issue".
The message comes after the Health Protection Agency (HPA) revealed last week that 28% of people with HIV (more than 21,000 individuals) are unaware they are carrying the virus.
According to the HPA, new national testing guidelines should recommend wider HIV testing in areas of the country where prevalence of the infection is greatest. Men and women aged 15 to 59 should be offered tests when registering with a GP or are admitted for treatment, it argues.
The letter, from MPs and charities, states: "Undiagnosed people are unaware of the specific risk to their sexual partners and so may not consistently use a condom; and since they are not on treatment, they are also likely to be more infectious.
It added: "Testing needs to be easy to access, not just in GUM clinics, but in GPs surgeries and in community settings accessible to high-risk populations.
"Knowledge is always said to be power. In the case of HIV infection, timely knowledge of your HIV status means life for you as you access life-saving treatment, and better public health for the country at large."