The on-going Chinese National Games confirmed its first doping case on Sunday as rower Guo Linna from Henan provincial team was stripped of the rowing semifinal after testing positive for banned stimulant.

Guo, a national team member and World Cup champion, may face a four-year ban by the Chinese Rowing Federation, and her provincial team's results were announced void. A senior official with the Chinese Olympic Committee Jiang Zhixue reaffirmed the country's zero tolerance to drug offenders.

The doping scandal has taken the spotlight from the domestic sports extravaganza which was already embroiled in alleged match fixing in the diving competition.

The embarrassments have challenged China's intensified efforts to ensure fair play at the quadrennial "mini-Olympics", which sees 10,001 athletes (just short of 11,028 at the Beijing Olympics) competing for 362 gold medals in 33 sports.

Organizers are keen to avoid unfairness at the 11th National Games, and have for time and again demonstrated their determination to fight against scandals including doping, age faking, biased judging and match fixing.

China's top sports official Liu Peng has vowed to strictly ban doping in sport, adding securing clean National Games serves the most important factor for a successful Games.

"All teams at the National Games have to be aware that sportsmanship and discipline, as well as anti-doping, are more important than winning gold medal," said Liu, director of China's State General Administration of Sports.

China was at the heart of several major doping scandals in the 1990s and early years of this century but its determination to avoid embarrassment at Beijing Olympics led to a clampdown on the use of banned substances.

Under the Chinese Olympic Committee rules, any athlete taking banned substances during the 11th Chinese National Games is banned for four years and will be expelled from the Games.

To fulfill the commitment, games organizers have set up a drug-testing department consisting of medical professionals.

Prior to the National Games, the sports administration and all its provincial branches have signed anti-doping contracts with their athletes. Furthermore, athletes have to pass an anti-doping examination to qualify for the National Games.

In the athletics event which is risky for doping violations, some 30 to 50 percent of track and field athletes, chosen by a random draw, will be required to take the written exam before or during the National Games in Jinan, Shandong province.

"The exam is not to create difficulties for the athletes, but to teach them how to protect themselves," said an official with the Chinese Athletic Association, adding athletes who fail the exam will be kicked out of the Games, and teams with over 40 percent of athletes failing the test will also be declared ineligible.

While intensifying anti-doping campaign, organizers also introduced a series of rules to guarantee unbiased judging at the domestic multi-sport Games slated for Oct. 16-28.

On the boxing arena, any communicating device used by the referees, including mobile phones and laptops, must be handed in before the games.

In the diving events, the Chinese Swimming Association (CSA) had issued a special regulation for the management of referees, warning any judge who committed misconduct would get alarmed for the first time and dismissed for twice.

All the 40 diving referees were chosen at random half an hour before the events started. To be stricter, sometimes nine referees were assigned for the individual events and 11 referees for the synchro events, even more than international events which usually require seven for the individual and nine for the synchronized.

In some heat events, such as men's 3m springboard and 10m platform, referees in power were facing the risks of being replaced by substitutes if any unfair conducts were detected.

However, an alleged judge scandal trumped the National Games in recent days as one of the judges in the diving competition accused another of manipulating the panel to decide the winners beforehand.

Deputy sports minister Xiao Tian denied the accusation, saying investigation by the State General Administration of Sports had shown the charges were groundless.

"The GAS will definitely not tolerate any match fixing. If it happens, we will even take legal action," said Xiao. "But it is not true."

From doping to conceding matches to alleged biased judging, scandals are not new to the domestic sporting extravaganza, at which provinces desperate to bring home glory and offer native athletes rewards for medals that can even surpass those offered to Olympic champions.

The 10th National Games four years ago in south China's Jiangsu province were also plagued with charges of match fixing and skewed judges in judo, rhythmic gymnastics and taekwondo.

Sun Yingjie, a former world championship bronze medalist, tested positive after finishing second in the 10,000m, a day after winning the Beijing Marathon. Olympic gold medalist Xing Huina was denied her gold in the 1,500m for elbowing an opponent.

Protests have also been lodged over events including tennis, badminton and weightlifting, 26 out of 111 matches in both the men's and women's events were forfeited following a walk-out by athletes and coaches complaining of corrupt officiating and bribery.