At least eight in 10 gay and bisexual men believe it is unlikely or highly unlikely that they will ever contract HIV, despite the fact that many have had unprotected sex, a new survey has shown.

The results were released to coincide with a new campaign from the Gay Health Network, which aims to encourage gay and bisexual men to get tested or retested for HIV, and be aware of their HIV status.

According to the findings, 83% of gay and bisexual men think it is unlikely or highly unlikely that they will contract HIV. Yet 70% of sexually active gay and bisexual men have had unprotected sex. Of these, almost one in 10 admitted to always having unprotected anal sex.

The survey involved 543 men, almost 100 of whom were gay or bisexual. It revealed that at least one in four gay or bisexual men have never been tested for HIV, while almost half of those who have been tested have not been tested in the last six months.

Commenting on the campaign, entertainer and gay rights activist, Rory O'Neill, who is himself HIV positive, called on people to get themselves tested.

"As someone who is HIV positive and leads a healthy life, I would encourage everybody to get tested. Testing is essential to prevent the spread of HIV, it also ensures that people who are HIV positive get the treatment they need early and can go on to lead a productive and normal life," he said.

According to figures from the Health Protection Surveillance Centre, 344 people were newly diagnosed with HIV last year. The highest number of new cases - 159 - was found among men who have sex with men. In fact, among this group, there has been almost a 180% increase in diagnosis rates since 2005.

As part of the campaign, a new online locator map is available that shows where you can get a free HIV or STI test in Ireland. It includes details such as addresses and opening hours. The map can viewed on Man2Man.ie. There are currently 32 test centres in Ireland which provide these tests free of charge.

"Taking a HIV test is a simple procedure. A doctor (or nurse) will take your sexual history, and the test takes a couple of minutes to perform. An advisor will talk you through the test, which is not painful, and results will take between one and four weeks," noted Dr Shay Keating a specialist in genitourinary medicine.

The Gay Health Network is working in partnership with Janssen and the Dublin AIDS Alliance