Civic and academic groups in South Korea, China and Japan have issued a joint statement, calling for the retraction of a controversial paper by a Harvard law professor regarding Japan's sexual slavery during World War Two.

The 39 groups, including South Korea's Asia Peace and History Education Network, said on Monday that the paper by J. Mark Ramseyer ignores many documents and testimonies that verify Japan's coercion of women and human rights violations.

The groups pointed out that Ramseyer's controversial claims that the women were voluntary prostitutes are nothing new, but are in agreement with claims made years earlier by those who denied Japan's responsibility behind the war.

Citing Ramseyer's past historical claims, the groups assessed that his hatred and mockery towards the victims and minorities reflect some academic and political perspectives that are classist, racist and colonialist.

The groups added that such controversy will be inevitable so long as Japan continues to deny fundamental remorse for its past actions based on racism and colonialism, as well as its infringement of human rights.