AUKUS, formed in 2021 between Australia, the UK and US to address shared concerns about China's rising military ambition, is designed to enable Australia to acquire nuclear-powered attack submarines in the 2040s.
But doubts have been raised about the future of the $US368 billion ($A560 billion) program after the Trump administration initiated a review of the deal to examine if it met its "American First" criteria.
Defence Minister Richard Marles, speaking alongside Foreign Minister Penny Wong and their British counterparts John Healey and David Lammy, said he remained confident about the future of US involvement on the eve of Australia and the UK signing a five-decade bilateral deal cementing their commitment.
"We continue to work ... very closely with the United States in progressing the optimal pathway to Australia acquiring a nuclear-powered submarine capability, to see the fruition of the AUKUS arrangement in all three countries," he told reporters in Sydney on Friday.
"Australia (continues) to make our financial contributions to that industrial base, we've made two contributions each of $US500 million ($A760 million) this year."
An Australia-UK treaty will be signed in Geelong on Saturday, and will allow "comprehensive co-operation" on the design, build, operation, sustainment, and disposal of AUKUS submarines.
It will also support development of personnel, workforce, infrastructure and regulatory systems for Australia's nuclear-powered submarine program.
British Foreign Secretary David Lammy said the treaty showed the strength of Australia and the UK's commitment to AUKUS.
"It's clear that the UK-Australia relationship is an anchor in what is a very volatile world, providing stability in troubled waters and a relationship that holds steady whichever way the geopolitical winds are blowing," he said.
British Defence Secretary John Healey said the UK was confident it could meet its obligations under the deal on industrial capacity to deliver SSN-AUKUS submarines, and was undeterred by the US review.
"Australia and the UK welcome the review because we see this as a chance for a new administration to renew their commitment to AUKUS and that's what we expect," he said.
Australia will pay $5 billion to support British industry to design and produce nuclear reactors to power the future AUKUS-class submarines.
Australia will acquire at least three Virginia-class nuclear-powered submarines from the US in the early 2030s.
On Sunday, the ministers will visit Darwin to observe joint military exercises known as Talisman Sabre, which comprise more than 30,000 personnel from 19 militaries.
The 2025 war games involve the UK's Carrier Strike Group, led by the Royal Navy flagship HMS Prince of Wales - the first UK carrier strike group to visit Australia since 1997.
