A South Korean civic group supporting "comfort women" on Thursday launched a foundation opposed to a landmark deal between Japan and South Korea over the long-standing issue.

The Foundation for Justice and Remembrance for the Issue of Military Sexual Slavery is headed by Chi Eun Hee, who served as minister for gender equality and family during the administration of former President Roh Moo-hyun in the early 2000s.

The civic group, the Korean Council for the Women Drafted for Military Sexual Slavery by Japan, has slammed the bilateral agreement reached in December last year, saying it does not reflect the victims' opinions.

Under the deal, Tokyo pledged to provide ¥1 billion ($9 million) for a new South Korean foundation aimed at helping aging former comfort women, who were forced into wartime brothels for the Japanese military.

The foundation launched Thursday is intended to counter the government foundation, which has yet to be set up.

Later Thursday, South Korean Foreign Ministry spokesman Cho June-hyuck reiterated, "The deal between the two governments should be fully implemented to achieve the goal" of resolving the issue finally and irreversibly.

Cho declined to comment on the launch of the rival foundation, only saying, "It's not appropriate to comment on a private group's activities."

The deal has been criticized by some of the victims, as well as activists and opposition parties, who have called on the Japanese government to admit legal responsibility for compensation.

The Korean Peninsula was under Japanese colonial rule between 1910 and 1945.