Up to 200,000 "comfort women" from Korea, China, the Philippines and elsewhere were forcibly drafted into brothels catering to the Japanese military during WWII, according to mainstream historians.
Outspoken Osaka mayor Toru Hashimoto said last week these women served a "necessary" role keeping soldiers in line, sparking outrage in China and South Korea and inviting US criticism.
In a weekend survey of 1,550 households conducted by the Mainichi Shimbun newspaper, 71 per cent of voters said Hashimoto's comments were "inappropriate" against 21 per cent who said the comments were "appropriate".
The United States on Thursday condemned Hashimoto's opinion as "outrageous". In response, he claimed that American troops abused Japanese women during their seven-year occupation after Japan's 1945 surrender.
China, South Korea and the Philippines have all voiced their disapproval at Hashimoto's comments, the latest episode in a decades-long controversy over interpretations of history in East Asia.
Despite repeatedly saying the "comfort women" system was wrong and that its victims deserved compassion and apologies, Hashimoto's initial outburst in which he indicated there was no formal state involvement has fanned anger.
China and South Korea frequently criticise what they say is Japan's unwillingness to accept blame and atone for its belligerence in the first half of the 20th century. Tokyo insists it has apologised enough.
