Japanese leaders have said Russia's attack on Ukraine poses a challenge to their own national security, and fear it may encourage North Korea to further threaten its neighbours and embolden China to use military force to push its territorial ambitions in the South China Sea and East Asia, including against nearby Taiwan.

Japan's presidency of the G7 industrial democracies in 2023 and its return for a two-year stint as a non-permanent Security Council member will give it a more conspicuous international platform to voice its concerns.

Hayashi also reiterated that Japan would make a fresh push for United Nations reforms next year to tackle a "dysfunctional" Security Council that has failed to address Russia's aggression in Ukraine.

"Since the start of the United Nations, the membership has not changed. It should reflect the current status of the world, not in 1945," he added.