The South Korean government says it will not send a representative to a memorial ceremony that will take place on Japan's Sado Island on Sunday to honor all those who worked at gold mines there.

The Sado Island Gold Mines in Niigata Prefecture gained UNESCO World Heritage status in July. South Korea at first objected to the move by saying people from the Korean Peninsula were forced to work at the site. But it eventually gave its consent on the condition that Japan faithfully carries out the recommendations issued by an advisory body to UNESCO.

Tokyo explained at the time that officials were planning to hold a memorial ceremony on the island annually to pay tribute to all those who worked at the mines.

A South Korean representative and relatives of deceased people who used to work at the mines were scheduled to attend the first event.

But the South Korean Foreign Ministry announced on Saturday that it had decided not to dispatch its representative to the ceremony. It added that the bereaved relatives would also not take part.

The ministry said it was difficult for the two countries to work out their differences and reach an acceptable agreement before the event because of insufficient time.

South Korean media say Seoul's decision comes after Tokyo said Parliamentary Vice-Minister for Foreign Affairs Ikuina Akiko would attend the ceremony as the government representative. The news outlets add that Ikuina had visited Yasukuni Shrine in Tokyo.

The shrine honors Japan's war dead. Chinese and South Korean leaders have criticized their Japanese counterparts for visiting the shrine. They are angry that those remembered include military and political leaders convicted of war crimes after World War Two.

South Korean Foreign Minister Cho Tae-yul spoke on a TV program on Saturday, expressing Seoul's intention to maintain communication with Tokyo. He said both countries should work to ensure that "the positive flow" in bilateral relations will not be disrupted.