The Supreme Court upheld a September, 2006, Osaka High Court ruling that the plaintiffs could not seek compensation because a 20-year statute of limitations had expired, according to court spokesman Takashi Ando and a statement issued by the plaintiffs' Japanese support group.

The decision was the latest by the top court this year, following earlier rulings that individual Chinese citizens have lost their right to seek redress from Japan following the 1972 signing of a Japan-China Joint Communique restoring bilateral ties. Beijing abandoned its right to claim war reparations from Japan under the communique.

The six plaintiffs in the latest case -- four former laborers and the relatives of two who died -- had demanded the government pay a total of 110 million yen (US$904,600; euro677,860) in compensation for forcing them into slave labor at nickel mines in Kyoto, about 370 kilometers (230 miles) west of Tokyo.

Judge Mutsuo Tahara agreed with the earlier ruling that the current government was not responsible for the wrongdoings of leaders who followed the wartime constitution, Kyodo News agency reported.

The court ruled that the plaintiffs lacked legitimate reasons to appeal, Ando said.

The laborers were brought to Japan in 1944 and forced to work at the Oeyama mines of Nippon Yakin Kogyo Co. under harsh conditions and with meager food, their supporters said in the statement posted on the Internet.

The six men returned to China in December 1945, four months after Japan's defeat. They originally filed a lawsuit at Kyoto District Court against the government and the company in August 1998 but reached a settlement only with the company in 2004. Under that deal, the company agreed to pay 3.5 million yen (US$28,800; euro21,580) to each plaintiff.

Japan's military shipped hundreds of thousands of men from China and other Asian countries to Japan to work in coal mines and factories during World War II to make up for domestic labor shortage. It also forced women into sexual slavery for Japanese troops.

Tokyo has refused to pay damages to individuals, claiming the issue was settled on a government-to-government basis in postwar treaties.