International Olympic Committee president Jacques Rogge called for government help on Friday to fight match-fixing and illegal betting as part of "ethical risks" that endanger the future of sport. He said the global success of sport -- with 750 million people practising competitive sports and more than one billion engaged in recreational sports -- faced challenges from doping, violence, racism and corruption. Rogge said corruption was mostly seen "in the field of match-fixing where the result of competition is being manipulated where there is illegal betting." "The IOC has taken the leadership in fighting against illegal betting and match fixing. But we need the support of governments," he said in a speech at an event in Tokyo marking the centenary of the Japanese Olympic Committee. "We are working very closely with major governments to try to set up a platform where the world of sport and the world of ministries and politicians can work together." Corruption in sport has been making headlines worldwide. Recently in Asia, football players in South Korea were indicted and sumo wrestlers in Japan were expelled from the sport after being involved in match-fixing scandals. Identifying doping as the "biggest threat on sport," Rogge said the IOC was making "bigger progress" than ever in fighting it with "zero tolerance". He said the number of doping tests had been doubled since the 2000 Sydney Summer Olympics. "While we will never be able to have zero doping, I must say and I can say with great pleasure that we are making a bigger progress and that today it is far more difficult to take doping than it used to be a couple of years ago." Rogge said violence, especially hooliganism, in and out of venues was the second major danger. "This is a major problem mostly in team sports, where we need a good association between the public and the sports authorities," he said. "Sport alone cannot solve it, but we have to lead by example." Rogge noted there had been "unacceptable racism against players coming from Africa" at venues and stadiums especially in Europe. He welcomed moves in many countries to legislate against racist behaviours.