New figures to be issued today at a sexual health summit show Australian doctors detected 995 new cases of HIV during 2008.

This was down fractionally from 1051 diagnoses in 2007, but Associate Professor David Wilson, of the University of NSW, said a change in data collation might have contributed to the decline.

''This last year is the first year in the last decade that we have not seen an increase ... but some of that might be tied to slight changes in methodology,'' Professor Wilson, the head of the university's surveillance and evaluation program for public health, said.

Australia's annual number of new human immunodeficiency virus diagnoses has increased by 38per cent over the decade, from 718 cases in 1999.

Gay men continue to account for most of the new cases of HIV, with 64 per cent of cases in 2008 occurring among men who have sex with men.

The next largest group (21 per cent) contracted HIV through heterosexual contact, while the remaining cases were linked to injecting drug users or ''undetermined''.

The latest figures take Australia to a total of 28,330 cases of HIV, leading to 10,348 cases of AIDS and 6765 AIDS-related deaths since records began.

At December 31 last year, there were 17,444 Australians living with HIV, though the number who go on to develop AIDS is in decline.

This figure peaked at about 1000 AIDS cases annually in the early 1990s, but it has since dropped to about 240 people a year since 2001.

Australasian Society for HIV Medicine president Jonathan Anderson said public health officials should lead a renewed effort to tackle the virus, since too many people were still turning up at clinics in advanced stages of HIV infection.

''I don't think another scare campaign would work,'' Dr Anderson said, giving the example of the infamous Grim Reaper-themed public awareness campaign.

''I think we need to explore more the rate of undiagnosed HIV in our society, it's hard to change behaviour but it's much easier for the health system to test more routinely for this.''