The Japanese government is expected to ratchet up pressure on Seoul by demanding an explanation for its inaction towards Tokyo’s decision to take the Dokdo issue to the International Court of Justice.

Japanese broadcaster NHK said if South Korea does not issue a response on the Japanese government's proposal to the ICJ, Tokyo will demand an explanation from Seoul over its objection.

The broadcaster said Japan is planning to inform the international community of South Korea’s “baseless” stance that Dokdo is South Korean territory.

The Japanese government is planning to send a formal verbal note on its decision to take Dokdo to the ICJ next week.

Meanwhile, Japanese Prime Minister Yoshihiko Noda sent a letter expressing his regret over President Lee Myung-bak’s comment regarding the Japanese emperor and Lee’s recent visit to the islands.