The ministry's panel said the 2015 agreement between Tokyo and ousted former conservative South Korean President Park Geun-hye was insufficient. "A victim-centered approach, which has become the norm when it comes to the human rights of women in times of war, was not sufficiently reflected and the deal was reached through give-and-take negotiations like an ordinary diplomatic agenda," said Foreign Minister Kang Kyung-wha in a statement.
Kang apologized on behalf of her government for "giving wounds of the heart to the victims, their families, civil society that support them and all other people because the agreement failed to sufficiently reflect a victim-oriented approach, which is the universal standard in resolving human rights issues".
The liberal administration of President Moon Jae-in claims that the previous administration's deal was not reached in consultation with the survivors, nor did it hold Japan legally culpable for the war crime or require Tokyo to provide direct compensation to the victims.
Instead, under the 2015 deal, Japan apologized and accepted "deep responsibility" for the comfort women's suffering, as well as started a $8.8 million fund on behalf of the victims.
Tokyo does not appear open to the idea of renegotiating the agreement. Japanese Foreign Minister Taro Kono warned that the agreement was the result of "legitimate negotiations" and any amendment to it could jeopardize Seoul-Tokyo relations.
The agreement claimed that both nations would "finally and irreversibly" put the wartime issue behind them, it having long cast a heavy shadow over bilateral relations. Seventy-two years after the end of WWII, fewer than 50 comfort women remain alive in South Korea. Seoul also agreed to stop pressing the issue as part of the 2015 deal.
"If [South Korea] tries to revise the agreement that is already being implemented, that would make Japan's ties with South Korea unmanageable and it would be unacceptable," Kono said in a Wednesday statement.
Reportedly, the 2015 deal also included a promise from Seoul to have statues symbolizing comfort women installed outside the Japanese embassy in Seoul and consulate in Busan removed. The statues were installed by activists to raise the public profile of the plight of the comfort women.
Activists have also staged a campaign to build similar statues in international cities, with San Francisco one of the highest-profile examples. The announcement from the city council led to the mayor of Japanese sister city Osaka to cut ties with San Francisco.
The Korean Peninsula was a colony of Imperial Japan between 1910 and 1945 and was the source of most of the comfort women forced to serve the Japanese army. Others came from China, the Philippines and other Asian nations that were conquered by the Japanese Empire. Many of the women enslaved at Japanese military brothels were lured there by promises of work as factory workers or nurses.
The Imperial Japanese military was infamously brutal in its treatment of captives and civilians, and the comfort women were no different. Approximately 75 percent of them died before the war ended as a result of beatings, physical torture, gang rape and sexually transmitted diseases. Many comfort women were also killed or forced to commit suicide in the last days of the war as Imperial Japan's defeat became imminent.
The UN criticized the comfort women euphemism in 2014, calling on Japan to admit that the women were "enforced sex slaves" and refer to them as such.