BEIJING - Expanding China's lottery industry is key to combating the growing level of illegal online sports gambling, which is already worth more than 1 trillion yuan ($146 billion) a year, said a leading lottery expert.

On one domestic website alone, gamblers placed 175 billion yuan in bets in 2009, said Wang Xuehong, executive director of the China center for lottery studies at Peking University.

Ministry of Public Security officials say gambling on sport hits a peak during major international events, such as the soccer World Cup, which opened in South Africa on Friday.