A former chief of the Osaka District Public Prosecutors Office on Friday pleaded guilty to raping a female subordinate prosecutor in 2018 while she was drunk.

Kentaro Kitagawa, a 65-year-old lawyer, said he does "not contest" the sexual assault accusation against him, saying, "I inflicted serious damage against the victim and I am deeply remorseful," in the first hearing for the case at the Osaka District Court.

When the intoxicated woman was taking a taxi to go home following a social gathering with Kitagawa and his colleagues on Sept 12, 2018, he forced himself into her taxi, took her to his official residence in Osaka and raped her there, prosecutors said in their opening remarks.

Kitagawa, who was the chief public prosecutor at the time, ignored the woman's pleas to stop assaulting her when she regained consciousness, telling her, "You are my woman now," the Osaka High Public Prosecutors Office said.

He raped her late that night until the early hours of the next day, according to the indictment and prosecutors.

"I was victimized by the top person at my organization, and my own dignity as a prosecutor was trampled upon," the victim said at a press conference following the hearing.

She was told he "would die if (the rape) was made public, which would inconvenience other prosecutors," she said.

Hailing from Ishikawa Prefecture, Kitagawa became a public prosecutor in 1985. He also served as the deputy prosecutor of the high prosecutors office and the head of criminal investigations at the Supreme Public Prosecutors Office.

Following his departure, he registered as a lawyer with the Osaka Bar Association.