To describe recent trends in the diagnosis of HIV infection in Australia.

Analysis of national surveillance system data for 1993-2006.

Number and population rate of new HIV diagnoses by year, exposure route and demographic characteristics.

Between 1993 and 2006, 12 313 new diagnoses of HIV infection were reported in Australia. From 1993 to 1999, the annual number of diagnoses declined by 32% from 1056 to 718, and then increased by 31% from 763 in 2000 to 998 in 2006. Between 2000 and 2006, diagnosis rates significantly increased in Victoria, Queensland, South Australia and Western Australia. The most frequent route of HIV exposure was male-to-male sex, accounting for 70% of diagnoses. Heterosexual contact accounted for 18% of cases, with just over half of these people born in or having a sexual partner from a high-prevalence country. Exposure by injecting drug use remained infrequent.

The number of HIV diagnoses has risen in the past 7 years, but not in New South Wales, which has long had the highest rates. The differences in rates between states/territories are likely to be due to divergent trends in sexual risk behaviour in men having male-to-male sex, which remains the predominant route of HIV transmission in Australia. There is a need for effective, innovative and evidence-based programs for HIV prevention, particularly among men having male-to-male sex.