The prime minister has previously said he was ready to hold talks with Kim, but the reiterated invitation comes after the North Korean leader travelled to Russia to met President Vladimir Putin this week.

That meeting sparked worries of a possible arms agreement after US officials warned Moscow was in search of ammunition to use in the Ukraine conflict.

"We would like to hold high-level discussions under direct control of the prime minister to achieve a summit meeting as soon as possible," Japan's Chief Cabinet Secretary Hirokazu Matsuno told reporters at a regular briefing.

Kishida "has been expressing his determination to directly face" Kim at "any time and without preconditions," said Matsuno.

Following a summit with Putin on Wednesday, Kim travelled to Russia's Komsomolsk-on-Amur, a far eastern industrial city where he reportedly visited a military aviation factory on Friday.

Longtime allies Russia and North Korea are both under rafts of global sanctions -- Moscow for its Ukraine conflict and Pyongyang for its nuclear tests.

Japan's Foreign Minister Yoko Kamikawa told reporters on Thursday that Tokyo was watching the Russia-North Korea talks "with concerns, including the possibility that it could lead to violations of the Security Council's ban on all arms-related material transactions with North Korea".