Cases of syphilis and gonorrhoea have doubled in Australia in the past decade, according to the latest data.
The information, released by the Kirby Institute of the University of NSW, revealed that in 2024, there 5866 diagnoses of syphilis around the country, and 44,210 of gonorrhoea.
Congenital syphilis, a condition that sees a pregnant mother pass the disease on to their infant, has also more than doubled since 2015, causing 34 infant deaths through the decade.
READ MORE: 'Note' left by Charlie Kirk shooting suspect under investigation
And chlamydia remains the most prevalent STI, with 101,742 diagnoses last year, though the rate remains steady.
HIV diagnoses, on the other hand, have fallen by 27 per cent in the past year, though mostly in Australia-born residents.
Other numbers showed there were significant gaps in sexual health in Australia.
READ MORE: Accused Kirk shooter's relationship with trans partner examined
One recent analysis from the Australian Survey of Health and Relationships found only 16 per cent of Australians aged 16 to 49 had ever been tested for an STI, and only 50 per cent had ever discussed sexual health with their doctors.
"These data, on a backdrop of rising STIs, are concerning," Kirby Institute epidemiologist Dr Skye McGregor said.
"Chlamydia, gonorrhoea and syphilis are easily treated and cured with antibiotics. Early testing, diagnosis and treatment prevents serious outcomes.
"HIV, while not curable, is highly treatable, and diagnosis and starting effective treatment early prevents poor health outcomes and interrupts onward transmission.
"These data are a reminder that regular sexual health testing, including syphilis and HIV, is crucial."
READ MORE: Accused Kirk shooter's relationship with trans partner examined
STI rates remain higher in Indigenous Australians, with chlamydia diagnosed at more than twice the rate, gonorrhoea almost four times higher, and syphilis more than five times higher, than in non-Indigenous people.
"These gaps are even starker in regional and remote areas," Robert Monaghan, a Bundjalung-Gumaynggir man and manager of the Yandamanjang First Nations Health Research Program at the Kirby Institute, said.
"What's needed now is real investment in culturally safe, community-driven health promotion, testing and treatment.
"Declaring syphilis a Communicable Disease Incident of National Significance is an important step.
"Sustainable change depends on culturally safe, community-led action."
READ MORE: These siblings started a business with a few hundred bucks. It's made $20 million
Men are also overrepresented in STI numbers, accounting for eight out of 10 syphilis diagnoses, and seven out of 10 gonorrhoea diagnoses.
But syphilis infections are increasing faster for women, quadrupling across the decade.
"It's important that everyone who is sexually active discusses sexual health with their partners, practices safe sex, has regular STI testing, and talks to their health care provider about their sexual health," McGregor said.
DOWNLOAD THE 9NEWS APP: Stay across all the latest in breaking news, sport, politics and the weather via our news app and get notifications sent straight to your smartphone. Available on the Apple App Store and Google Play.
