The 34-year-old, who won gold medals in the 48-kilogram category at Sydney in 2000 and Athens in 2004, plans to combine her new career if she is elected in July with trying to qualify for the London 2012 Olympics.

Tani, who has become a role model for young Japanese women for combining her successful career with being a mother of two children, said: "While raising my children, I would like to take on other challenges.

"I will remain active in judo.

"I will try to win the gold in London."

Tani, who has also won a record seven World Championship titles as well as two silver and bronze Olympic medals, was unveiled to the media at the DJP's headquarters in Tokyo.

She said: "I'd like to give it all my best, with enough love to envelop the earth."

Tani, whose husband Yoshitomo Tani, plays for the Yomiuri Giants baseball team, said she was initially approached by DPJ Secretary General Ichiro Ozawa in March about running for the Diet, Japan's electoral chamber, but she did not decide on her candidacy until late last month.

She said: "I'd like to work hard under the strong leadership of Mr. Ozawa."

Tani has resigned from her job at Toyota to concentrate on her political career.

Ozawa said: "There's little time left before the election.

"We plan on providing strong backup so that those who are familiar with Mrs Tani, those who support her, will lend us a hand."