Japan on Wednesday rejected South Korea's complaints concerning new export restrictions, telling the World Trade Organization that its policies targeting Seoul were necessary for "national security purposes."
At a closed-door meeting of WTO's General Council, South Korea had earlier spoken out against Japan's decision to restrict exports of chemicals vital to Seoul's world-leading chip and smartphone industry.
"The measure referred to by Korea is based on the export control system for national security, and is not an appropriate agenda for the WTO," Tokyo's delegation replied, according to copy of the remarks sent to AFP by Japan's U.N. mission.
Seoul has argued that the Japanese measures were a politically motivated response to a South Korean High Court decision ordering Japanese firms that used forced labour during World War II to compensate victims.
Japan told the General Council, the WTO's top negotiating forum, that it had no choice but to act.
"Korea stated that the measure taken by Japan went against the free-trade system. Free trade, however, does not mean allowing trade in sensitive goods and technologies that can be diverted to military use, without any controls or conditions," Japan said.
Discussing the measures in terms of their economic impact "is not acceptable," given the security implications, the statement added.
Tokyo has previously said that its trade restrictions were made necessary by a "loss of trust" in relations with Seoul, while also accusing South Korea of improperly handling exports of sensitive materials from Japan.
Japan has also announced plans to remove South Korea from a so-called white list of countries that face minimum trade restrictions, which would further impact bilateral trade.
South Korea has said it is weighing legal action at the WTO, although no case has been filed.