The return rate of the traditional lottery is on a par or more so than those overseas but the sports lottery is slightly lower, resulting in many players participating in overseas lotteries via underground networks.

Although there isn't a precise survey, widely accepted data based on statistics from betting shops during the World Cup and European Cup is that 70 to 80 percent of the stakes come from Chinese customers, among whom about 70 percent are from the Chinese mainland, Su said.

Meanwhile, about half of the 160 billion yuan revenue of the gaming industry in Macao is from Chinese mainland players.

"On the Chinese mainland, the revenue of the underground lottery industry is no less than the official sales figures," Su said.

The lottery industry can be an effective measure for adjusting a country's economy. A good example is Singapore opening its lottery industry to battle the Asian financial crisis.

However, in China, the lottery business has always been a sensitive issue because gambling is strictly forbidden in the constitution, Su said.

"The lottery industry is developing fast among our neighbors such as Macao, Far East Russia, Vietnam and Japan, which have already formed a 'ring of encirclement' around the Chinese mainland," Su said.

"It's like if you like soy sauce and you find a group of people who open a soy sauce store near your home," Su said. "The best way is to make your own."

weitian@chinadaily.com.cn