It is believed that the credit crunch would also cause incomes to drop as clients would prefer cheaper service providers or meet sex partners through internet sites.
In Queensland, there are nearly 3400 sex workers, and according to estimates by industry analyst IBISWorld, it will go to about 3730 by 2008-09.
Also, the revenue for the state's legal brothels is expected to fall from 244 million dollars in 2007-08 to an estimated 239 million dollars in 2008-09.
And with the sex services tipped to stay in high demand in mining towns, the boom in resources might just provide some protection to the industry in the Sunshine State.
"When unemployment increases, you tend to see a rise in sex work as women look for a quick way to make some money," Brisbanetimes.com.au quoted IBISWorld analyst Ed Butler as saying.
However, figures have revealed that with the number of workers rising, customers are actually cutting their spending.
Butler said: "When there is an economic downturn, people don't just stop going to brothels, they just use cheaper services, so it is those high-end and mid-range services that will suffer.
"Queensland and Western Australia are not seeing as big a drop in revenues as other states because mining towns are boom towns for prostitution; there are more men with higher disposable incomes and, let's face it, not much else to do."
And the downturn is has shown effect in the entire nation, what with Australia's 1.22 billion dollars prostitution industry coming on the verge to shrink by 6 per cent to 1.15 billion dollars next financial year.
Butler said the biggest blow would come to workers, mainly single mums and students.
He also said that the demand for sex services tended to stay stable but sex worker incomes would keep falling.
He said: "It's a vice industry, like alcohol and tobacco. People behave like it's a necessity as opposed to a luxury service.
"What happens when you've got a period like now is that people take their business from their mid-range providers to the cheaper providers, whether they are legal or not . . ."