Australia, the UK and the US said they were "considering cooperation" with Japan on the AUKUS security pact, just hours before the US president was due to meet his Japanese counterpart.
In a statement, the AUKUS partners said Japan's "strengths and close bilateral defence partnerships" with states meant it was a contender for participation.
"Since the inception of AUKUS, our countries have made clear their intention to engage other participants in Pillar II projects as our work progresses," the statement said.
"Over the past two and a half years, we have built a strong, trilateral foundation to deliver advanced military capabilities with speed and scale."
AUKUS was established in 2021 and has two main practical goals: Pillar I aims to provide Australia with a fleet of nuclear submarines.
Pillar II focuses on developing advanced military capabilities, such as artificial intelligence, underwater drones and hypersonic missiles.
The statement said the group will consider technological innovation, funding, industrial advantages and the ability to adequately protect sensitive data and information when seeking future capabilities.
Australian Prime Minister Anthony Albanese told reporters in Canberra that Japan's participation would only be for Pillar II of the agreement, not for broader membership.
"Japan is a natural candidate for that," he said.
The statement comes just hours before Prime Minister Fumio Kishida is due to meet US President Joe Biden at a summit where the two are expected to discuss Japan's possible future in AUKUS "advanced capabilities" projects. /BGNES
