Addressing the United Nations General Assembly, Kishida said that Japan still stood by diplomacy set out two decades ago by former prime minister Junichiro Koizumi on his historic visit to Pyongyang.

"Japan is prepared to engage in dialogue on matters of mutual concern," Kishida said.

"I am determined to meet with Chairman Kim Jong Un without any conditions and will miss no opportunity to take actions with all my dedication," he said.

Kim met three times with former US president Donald Trump, easing tensions but reaching no permanent solution on its nuclear program.

Japan is a close ally of the United States but some in Tokyo were privately uneasy with the outreach to North Korea, an arch-enemy that abducted Japanese citizens in the 1970s and 1980s to train its spies.

North Korea recently passed a law declaring its readiness to launch preventive nuclear strikes, raising concerns that the impoverished state may soon resume tests.

US President Joe Biden's administration has voiced a readiness for working-level diplomacy with North Korea but has found little interest in return.