A Beijing court has accepted a lawsuit filed by former forced laborers and their surviving dependants demanding apologies and compensation from Japanese companies over involuntary work during World War II.

It is the first time such a case has been accepted by a Chinese court.

Kang Jian, the lawyer representing the Chinese plaintiffs, confirmed that they have received notice of filing the case from No 1 Intermediate People's Court of Beijing and that the number of claimants has increased to 40.

"There is no reason to lose the case, based on the proof and facts we have," Kang said.

The group is seeking compensation of 1 million yuan each, as well as apologies from Mitsubishi Materials and Mitsui Mining and Smelting to be published in mainstream media in China and Japan.

Zhang Shijie, one of the plaintiffs, said he felt relieved for the acceptance of the lawsuit as it has for so long been rejected.