CHLAMYDIA, gonorrhoea and syphilis are on the increase, especially among Australia's younger generation, but HIV notification rates have remained stable in the past decade.
Chlamydia was the most frequently reported notifiable condition with almost 80,000 new notifications for persons aged 15 years and over in 2011.
An Australian Bureau of Statistics report into Australian social trends, released on Tuesday, found 82% of these notifications related to people aged between 15 and 29 years.
Chlamydia - a bacterial infection that can infect the prostate, urethra and testes in men and the cervix, uterus and pelvis in women - has more than tripled over the past decade.
Notifications for Chlamydia were nearly seven times the rate of the next most frequently reported STI, gonorrhoea.
While sexually transmissible infections predominantly affect younger Australians, the infection rates for older age groups are increasing too.
STIs, such as syphilis, affected more people aged 30 to 44 years than those aged 18 to 29 years.
While HIV rates have remained mostly stable in the past decade, Queensland had the highest rate for newly diagnosed HIV in 2010.