The competition has led to calls by Australia's casino mogul, James Packer, for the federal and state governments to try to lure back these high-spending Asians.
Packer's two casinos, Crown in Melbourne and Burswood in Perth, have seen turnover from high-rollers drop 8 % in the six months to Dec 31.
Burswood suffered more, with VIP revenue down 14.3 %, compared with Crown's 5.5 % fall.
Australian casinos bring in about A$ 700 million (US$ 895 million) a year from VIP gamblers, who contribute to about 15 % of all casino revenue, according to a Merrill Lynch analysis.
Casinos such as Crown tend to focus on attracting high-rollers from China and Hong Kong. Tourists from Taiwan, Korea, Malaysia, Singapore and Indonesia also make high-spending visits to Australian casinos, according to the Australian Gaming Council, which represents the industry.