China's Olympic judo champion, Tong Wen, is determined to defend her title at the London Games despite receiving a two-year ban for doping, which will last until September next year.

Tong became the first Chinese Olympic champion to be banned for doping when the winner of the women's 78kg section at the 2008 Olympic Games failed a test at last August's World Championships in the Netherlands. She tested positive for the banned substance clenbuterol.

Tong was stripped of the gold medal she won at the event, which was her third straight title at the Worlds, but she did not have to give up her Olympic medal.

The 27-year-old insists she is innocent but will not appeal the decision.

"I was so shocked when I heard the news. How could I not have drugs for the Olympic Games but for the World Championships? With my strength and ability, I don't have to use drugs at all. I have a clear conscience," Tong, who won the 2009 Worlds with five straight ippons, said.

"But there is no way to change the result of the test and I will not argue it. I just want to remind all the athletes of food safety," said Tong, claiming she may have ingested the substance, which is used to keep pigs lean, from pork she ate.

Although the ban will keep her from defending her title at November's Asian Games in Guangzhou, it has not shaken her determination to win another Olympic gold medal at the London Games.

"I will not give up the 2012 Olympic Games. I am looking forward to proving myself again in London," said Tong, who is now training in her hometown of Tianjin and recovering from a waist injury which forced her to quit last year's National Games.

"I will have more than half a year to compete before the London Games (after the ban ends). I believe I can still qualify for the Games."