South Korea said Friday it wants an investigation by the United Nations or another international body as it continues to reject Japanese claims that Seoul could not be trusted to faithfully implement sanctions against North Korea.

Kim You-geun, deputy chief of South Korea's presidential national security office, said South Korea has been thoroughly implementing UN sanctions against North Korea over its nuclear weapons program. He demanded that Japan provide evidence for claims made by Prime Minister Shinzo Abe and his conservative aides that there may have been illegal transfers of sensitive materials from South Korea to North Korea.

Tokyo last week tightened the approval process for Japanese shipments of photoresists and other sensitive materials to South Korea, saying such materials can be exported only to trustworthy trading partners. The move, which could potentially hurt South Korean technology companies that manufacture semiconductors and display screens used in TVs and smartphones, has triggered a full-blown diplomatic dispute between the countries that further soured relations long troubled over Japan's brutal colonial rule of Korea before the end of the Second World War.

Kim said the Seoul government proposes Japan accept an inquiry by the UN or another international body over the export controls of both countries to end "needless arguments" and to clearly prove whether the Japanese claims are true or not.

"If the result of the investigation reveals that our government did something wrong, our government will apologize for it and immediately apply measures to correct it," said Kim, reading a prepared statement on live TV.

"If the result shows that our government has done nothing wrong, the Japanese government should not only apologize but also immediately withdraw the exports restrictions that have the characteristics of a [political] retaliation. There also should be a thorough investigation on [any] Japanese violation," he said.

South Korea has denied the Japanese allegations that it allowed sensitive materials to reach North Korea. The Foreign Ministry in Seoul summoned a Japanese Embassy official on Monday to protest Abe's comments that questioned the credibility of Seoul's sanctions implementation.

South Korea's trade minister on Tuesday said an "emergency inspection" of companies that process and export the chemicals imported from Japan found no sign of illegal transactions allowing them to reach North Korea or any other country affected by United Nations sanctions.

Meanwhile In Tokyo, export officials from both sides sat down together on Friday the first since Japan tightened the approval process for shipments to South Korean companies. The officials made no comments immediately.