The surge in HIV diagnoses - up 24 per cent in NSW between 2011 and 2012 - has prompted the Rudd government this week to announce a $25 million prevention program to address the problem.

But experts say it is growing complacency around the disease that needs to be tackled.

''HIV is no longer regarded as a death sentence,'' said Professor Andrew Grulich, head of the HIV and Epidemiology and Prevention Program at the University of NSW's Kirby Institute.

''People are less fearful now. It is a manageable illness but it can still take years off your life.''

In the past 10 years, he said, reports of unprotected sex have been rising slowly, and about 20 per cent of gay men in Sydney report unprotected sex with casual partners in the past six months.

But the increase in rates of unprotected sex has been accompanied by more people getting tested.

''We are in the middle of a revolution in HIV testing,'' Professor Grulich said.

The changes in testing involve the roll out of rapid HIV testing, where patients get results in 20 minutes or less, and the roll out of testing at community sites and sexual health clinics.

Professor Grulich said Australia is investigating home-based HIV testing, something that is already in use in the US.

''We need to test a lot more. On average, a person with HIV is diagnosed three to four years after infection. They may be spreading HIV without knowing it,'' he said.

The chief of the AIDS Council of NSW, Nicolas Parkhill, said improvements in treatment - and a sharp decline in mortality rates over the past 20 years - meant people perceive the risk of HIV differently.

''Gay men just don't see their friends dying anymore,'' he said.

''The key is to scale-up testing initiatives so that people who are positive can go on treatment straight away. Treatment has a big prevention impact.''

Social networking, gay dating websites and apps such as Grindr, which enables gay men to meet other gay men, have fuelled the increase in HIV diagnoses, said Professor Don Smith, the director of clinical services at the Albion Centre.

''People don't have to work hard to find a partner anymore,'' he said. ''You can go online and find people looking for sex within 200 metres around you.

''In the gay community there appears to be a degree of ambivalence … that HIV isn't so bad. The advances in treatment have taken the edge off the perceived seriousness of the disease.''