IN A profession notoriously resilient to hard times, online dating sites threaten to do what the global financial crisis could not - send the sex services industry broke.

The $1.2 billion industry has bled $74 million over the past financial year, with brothels taking the hardest hit. In contrast, the market for exotic dancers and strippers, albeit starting from a small base, has steadily grown.

Sex is up there with tobacco and alcohol, according to the independent business information analyst IBISWorld. Recessions and depressions appear to have little impact on abstinence.

But while prostitution has proven through the ages to have the stamina to withstand the vagaries of the economic climate, the digital age may prove to be the profession's nemesis.

A senior analyst at IBISWorld, Edward Butler, who used industry surveys and Australian Bureau of Statistics data to crunch the numbers, said the 6 per cent contraction the sex industry experienced in the last financial year was most likely attributable to the surge in online dating sites which allow people to be frank about their penchant for casual sex.