Under the new rules, Japanese companies are required to apply for an individual license to export the materials to South Korea, a process that can take up to 90 days.

Other materials crucial in chipmaking and digital screen production -- fluorinated polyimide, etching gas and photoresist -- earned approval for export in August and September.

Experts say Japan's latest approval appears to be a veiled attempt to make its case that its restrictions do not run counter to international trade norms under the World Trade Organization.

South Korea claimed Japan's measure is a discriminatory act directly targeting it and apparent retaliation against last year's South Korean Supreme Court rulings ordering Japanese firms to compensate South Korean victims of forced labor during Japan's 1910-45 colonial rule of the Korean Peninsula.

(Yonhap)