South Korea and Japan are expected to inaugurate their new ambassadors to Tokyo and Seoul, respectively, next month after they recently endorsed each other's designations, multiple sources said Thursday.

Last week, Tokyo gave diplomatic consent to Seoul's designation of Kang Chang-il, a former four-term ruling party lawmaker, while its nomination of Koichi Aiboshi, the current ambassador to Israel, has also been endorsed by Seoul, the sources said.

The diplomatic green light came as Seoul seeks to improve ties with Tokyo strained over trade and wartime history, in part to enlist international cooperation to resume stalled nuclear diplomacy with North Korea.

The two countries have also been expected to seek ways to patch things up ahead of next month's launch of the US administration of Joe Biden, who has stressed stronger cooperation with America's democratic allies to shore up its global leadership.

The prospects of Kang's appointment initially appeared murky, amid reports that conservative Japanese politicians oppose him due to his 2011 visit to a set of disputed islands at the center of a long-running spat between Japan and Russia, and other issues.

Regarding Japan's consent to Kang's appointment, a Seoul official refused to confirm it but said, "Things have been going smoothly regarding that."

The designation of the new envoys raised hope for greater bilateral cooperation in addressing a series of pending issues, including legal proceedings to compensate South Korean victims of Japan's forced labor during Tokyo's 1910-45 colonization of the Korean Peninsula. (Yonhap)