TOKYO (AFP) - Japan's Mitsubishi Materials said on Wednesday it signed its first compensation settlements with Chinese wartime forced labourers, beginning a project to reach deals with more than 3,000 former workers or their descendants.

Under the landmark deal, the Tokyo-based smelter and raw materials company said it reached settlements with three former Chinese labourers compelled to work during World War II at mines in Japan, including a payment of 100,000 yuan (S$21,000) each.

Japanese atrocities in China during the war years remain a source of periodic tension between the two countries, which have often struggled to overcome the legacy of the conflict.

Tens of thousands of Chinese were forcibly sent to Japan to work in factories and mines during World War II to fill a manpower shortage arising from Japan's massive military mobilisation as it invaded China and countries in South-east Asia.

At a signing ceremony in Beijing, Mitsubishi Materials "expressed its sincere apologies regarding its historical responsibility to the former labourers".

They accepted the apologies, the company said in a statement.

The three were among 3,765 Chinese forced labourers who were known to have served in 10 mines operated by Mitsubishi Mining, its wartime predecessor, the company said.

The settlements have won endorsements from several Chinese groups which support the former labourers and their family members, it said.

As a part of the initial agreements, the company said it would set up a fund in China to support activities such as locating other former workers or surviving families.

The company also said it would build memorials at places and mines where the labourers were put to work.

The deal is one of the biggest of its kind to be reached by a Japanese company, public broadcaster NHK reported, citing a lawyer representing the workers.

Wednesday's settlement was initially not widely reported in China, with the China News Service carrying a one-paragraph article online.

Asked about the deal at a regular briefing in Beijing, foreign ministry spokeswoman Hua Chunying said the government was aware of it.

"The forced recruitment of slave labour was a great crime committed by Japan," she said. "We hope that Japan will take a responsible attitude toward history."

The Japanese government reached a series of official reparations deals with countries it colonised or invaded during the first half of the 20th century.

It also invested heavily in many of them in the decades after the war as well as providing development assistance in the form of low-interest yen loans.

Mitsubishi Materials last year made a landmark apology to US prisoners of war forced to work in its mines during the war, seven decades after the conflict came to an end.

The Japanese government officially apologised to former American POWs five years before that.

The sprawling conglomerate, which makes everything from cement to electronics, forced about 900 US POWs to labour at four mines in Japan.

Thousands of other US prisoners were pushed into slave labour at Japanese firms during the war.