Visitors look at display at Sado Kinzan Gold Mine historic site in Sado, Niigata prefecture, Japan, Nov. 23. AP-Yonhap

The Japanese government on Sunday expressed regret over South Korea's decision not to attend a memorial ceremony in Japan honoring forced labor victims, including Koreans, at an old Japanese mine complex.

The Japanese Embassy in Seoul made the remarks in response to a question by Yonhap News Agency, a day after South Korea decided not to attend the ceremony on Japan's Sado island amid controversy over Tokyo's decision to send a senior official with hard-line views on history to the event.

The Japanese Embassy said Seoul and Tokyo had been in "polite communication" over the memorial event, but it "would be regrettable" if South Korea does not attend the memorial service.

South Korea's decision came shortly after Japan said that Akiko Ikuina, a parliamentary vice minister at Japan's foreign ministry, will attend the ceremony as the government representative.

Critics said her attendance at the ceremony would upset the eleven family members of the Korean victims who were planning to attend the event. (Yonhap)