The admission comes after Rina Gonoi submitted a petition signed by more than 100,000 people demanding an independent probe into the allegations.

General Yoshihide Yoshida, who leads the Ground Self-Defense Force, said the probe had found that Gonoi, now 23, routinely faced sexual harassment and sexual assault at her unit and during training sessions.

"As the representative of the Ground Self-Defence Force, I deeply apologise to Ms. Gonoi, who has experienced pain and suffering for a long time," Yoshida said during a press conference.

The probe is continuing, and punishments and personnel decisions will follow upon its completion, an army spokesman told AFP.

Among various other charges, the army admitted that Gonoi was touched and harassed by multiple male colleagues while on a training exercise in 2021, a year after she joined the force.

She went public after prosecutors dropped their formal investigation into the case on the grounds of insufficient evidence.

A month ago, she made a public appeal to the ministry to investigate her charges, submitting the petition.

"There are many other people, including former senior female colleagues, who have faced sexual harassment," Gonoi told reporters in August after a brief meeting with defence ministry officials.

"I thought nothing will ever change if someone doesn't stand up and take action."

She said her action had prompted more than 100 allegations of sexual harassment and bullying in Japan's armed forces from women and men.

Japan's developed economy scores highly on education and healthcare for women, but its male-dominated society has long lagged behind industrial peers in placing women in boardrooms and in high public office.

Government data shows just four percent of rape victims report the crime to police.