TOKYO (AFP) - Allied soldiers liberating France during World War II raped French women after pushing back the Germans, an outspoken Japanese politician has claimed, as Tokyo comes under pressure over its wartime system of sex slavery.

Mr Toru Hashimoto, the mayor of Japan's second city Osaka who was once seen as a future prime minister, argued in a weekend speech that Japan must admit its own historical wrongdoings while also pointing out the mistakes of others, the Mainichi Shimbun said.

"After landing in Normandy, allied soldiers raped French women. 'Comfort stations' were built after things became too much," he said in the speech, using a euphemism for brothels, according to the newspaper.

"It is a historical fact. It is an unfortunate past. We must never repeat it," he said in the public address.

The comment is the latest instance of a right-wing politician jumping feet-first into the sensitive topic of the Japanese use of coerced prostitution during World War II, which saw thousands of women - mainly Koreans - forced to work in brothels.

Japan has officially apologised for the system and maintains that a treaty normalising ties with South Korea decades ago settled the issue.

But the two Koreas continue to say Tokyo is not contrite enough - a stance that is reinforced every time a senior politician equivocates or attempts to play down the subject.

Conservatives - including Prime Minister Shinzo Abe - feel Japan is unfairly singled out for wrongs that were more widespread than their accusers admit.

However, historians agree that while there were rapes by allied soldiers in Normandy, there is no generally accepted evidence of officially-sanctioned sex attacks by any military during World War II, other than the Japanese.

"Europeans and Americans say 'Japanese used sex slaves'. We have to educate Japanese who would be able to argue and reply to them, 'We were wrong, but you were wrong as well'," Mr Hashimoto said in the speech, according to the Mainichi.

Mr Hashimoto, whose small opposition party has recently fractured, is well known for stirring controversy. Critics suggest he is playing to a narrow but vocal domestic gallery with little regard for international implications.

Last year he claimed the comfort women system served a "necessary" role by keeping battle-stressed soldiers in line, sparking outrage in Asia and inviting US criticism.