The troubling figures come amid growing concerns about antibiotic resistance.

Data from ACT Health reveal chlamydia rates appeared to have stabilised in the past five years. In the 2009-10 financial year 1048 cases were diagnosed compared to 1001 this year. Diagnoses in the past five years were highest last financial year when 1266 new cases were diagnosed.

HIV increased from 11 new cases in 2009-10 to 23 case this year while gonorrhea has surged from 52 cases to 114 in the same period. There were 116 gonorrhoea diagnoses last financial year.

Diagnoses for HIV include ACT residents who had their first notification in Australia. It includes newly acquired infections as well as those who may have had the virus for an unspecified time.

There were 10 new diagnoses of "infectious" syphilis - carried it for less than two years - this financial year, compared to 11 in 2009-10. Those diagnosed as having had syphillis for two years or more, which is considered unlikely to be infectious, rose from 19 cases in 2009-10 to 24 this financial year, double the number last year.

Canberra Sexual Health Centre director Sarah Martin said HIV and gonorrhoea cases were rising nationally and in the ACT, which was cause for concern.

Although gonorrhoea could be treated with antiobiotics, treament was becoming more complex as more antibiotic- resistant strains emerged, Dr Martin said.

"Across the world, we are concerned about where gonorrhoea is heading. We're unable to say exactly at what point we might not be able to treat it but certainly it's an infection that needs taking very seriously in terms of diagnosis and effective contact tracing to try and reduce the number of diagnoses," she said.

"HIV and gonorrhoea are passed on through unprotected sex and we do have some data to support an increase in unprotected sex, particularly between casual partners. Gonorrhoea is also easily passed on through oral sex and people can carry gonorrhoea in their throats without much in the way of symptoms."

Dr Martin also warned that gonorrhoea increased a person's risk of contracting HIV if they were exposed to it.

HIV had become "less visible" because treatment was now much simpler and more effective, enabling people "to get on with their lives".

There was also HIV medication which could reduce a person's risk of contracting the virus after exposure, but it was crucial it be taken as soon as possible, she said.

"There's not the same level of fear about HIV and that means prevention messages today are much more complicated," she said. "While treatment for HIV today is very effective, HIV still changes life enormously and prevention does still matter."

Dr Martin said it was important for people who might have exposed to or at risk of STIs, including HIV and gonorrhoea, to be tested regularly.

While it was pleasing that rates of chlamydia appeared to have stabilised, it would be better if they declined, she said.

"Vaccine coverage in the ACT has been good. At the sexual health centre, we very rarely see genital warts in somebody who has been vaccinated. This year, across the country, the next phase of the HPV vaccination program has been rolled out to include boys so boys from year 7 will be vaccinated against HPV. That is a development which we can feel extremely proud of as a country."

Dr Martin said condoms were still the best way to prevent STIs.

Lecturer and public health physician at the National Centre for Epidemiology and Population Health Stephanie Davis said disease rates tended to fluctuate between years and in small jurisdictions like the ACT, relatively small numbers could appear as large changes.

"With any STIs, the number of diagnoses made is reliant on both the amount of disease in the community but also on any kind of change in testing practices so if you do more tests, you're going to end up with more cases," Dr Davis said.

"I think we still need to reinforce those messages around safe sex and that prevention is better than the cure, but we don't even have one for HIV."

There are a number of sexual health programs, including those like as the Sexual Health, Lifestyle and Relationhsips Program (SHLiRP) which brings sexual health screening clinics as well as sexual health and sexuality education to secondary colleges in the ACT.

For more information or to find out about STI testing, visit: http://health.act.gov.au/sexualhealth/.