Health authorities have warned Victorians to stay alert, with the state leading the country in local transmission of monkeypox.
There have now been 40 cases of monkeypox in Victoria, with around 15 to 18 active cases.
The state recorded its first case of monkeypox on May 16, after a returned traveller from the United Kingdom tested positive for the virus.
Deputy Chief Health Officer for Communicable Disease Deborah Friedman said the past two weeks have shown a "significant increase" in locally acquired cases.
"Just about half of our 40 cases have been acquired within Victoria rather than overseas," she said.
"We are really the only state in Australia that's seeing such an increase of local transmission."
Victoria's cases have also been centred predominantly around Melbourne and health authorities believe cases will rise further.
At-risk communities urged to be on alert
She said that while monkeypox could spread from the close intimate contact of any two people, it had mainly been centred around LGBT communities.
"Where we're seeing it now is within the gay, bisexual and men who have sex with men community," Dr Friedman said.
A weekly nude event at a Melbourne nightclub went on hiatus last month following concerns about monkeypox transmission.
Dr Friedman said the cancelling of high-risk events made sense in the current health climate.
"From a public health perspective it's a reasonably sound choice to cancel some events, especially some events that are going to result in very close or intimate contact," Dr Friedman said.
Victorians are encouraged to self-monitor for symptoms including fever, sore throat, muscle aches, a rash and swollen lymph nodes, and keep contact details of those they have intimate contact with for contract tracing purposes.
Returning travellers from monkeypox hotspots such as North America and Europe are also strongly recommended to monitor for symptoms for at least three weeks.
The monkeypox strain that is infecting Australians is thought to have a mortality rate of around 3 per cent.
Vaccines are here, but may have come too late
Dr Friedman said that while local transmission has been escalating in the past two and a half weeks, monkeypox vaccines only became available in the past 10 days.
"So we, unfortunately, missed a window of opportunity to potentially have been able to intervene earlier," she said.
Vaccines have been rolled out across sexual health clinics across Melbourne, with sex workers, HIV-positive people and those who have had direct contact with monkeypox cases eligible.
Victorians are warned that vaccine eligibility criteria and supply are limited during August and September while health services wait on further supply.
The government expects 20,000 doses to be available by September.
People who are eligible and reside in regional Victoria may access the vaccine via a regional local public health unit.
