On the other hand, the survey of 600 sex workers has also suggested that prostitutes in Melbourne fare the worst.
However, the experts have warned that if the new Liberal state government sticks to regulate the industry, the sex workers in Perth will eventually get the "rawest deal"
The report, which will be presented at a major sexual health conference revealed that all three cities have a "thriving" sex industry, with nearly 400 brothels in Sydney, 160 in Melbourne and 40 in Perth.
The experts claimed that Sydney was the "highest risk" city for sexually transmitted infections, because that's where the migrant sex workers from Asia congregate. But still, it turns out to be the safest place for them.
"What we found is that sex workers (in Sydney) are not frightened to seek proper health services because there are no legal issues stopping them," News.com.au quoted Basil Donovan, a professor in sexual health at the University of NSW, who led the survey, as saying.
The poll indicated that Melbourne was a different story altogether- with a decriminalised system where brothels are still required to register their workers so they can get monthly health check-ups.
"That might sound nice but it's extremely expensive, unnecessary and an intrusion on these women's bodies, and it scares women away from being registered at all, which drives the whole thing underground," said Donovan, who argues the law should be reformed.
He added: "It is simply a stupid system that creates an underclass of hidden sex workers who may very well suffer much worse health outcomes, if we could even track them down to find out."