The former head of Australia's submarine squadron has urged Australia against outsourcing boat construction overseas, as bureaucrats express confidence the US won't scuttle AUKUS.
A parliamentary inquiry on Thursday ran the ruler over the Geelong treaty, a 50-year AUKUS co-operation agreement between Australia and the UK signed in July.
Under AUKUS, the US has promised to sell at least three Virginia-class nuclear-powered submarines to Australia from the early 2030s.
A submarine solution closer to home should be examined instead, retired navy rear admiral Peter Briggs argued.
"Depending on an overseas supply chain for such a critical capability as our submarines is a folly," he told the inquiry.
Mr Briggs had serious concerns with the plan, including limiting Australia's commercial interests, and said the nation should build more submarines as it had done previously with the diesel-electric Collins class.
"There is no minimum protection in the treaty for a guaranteed work share for genuine Australian industry," he said.
"The Collins project has established a viable submarine supply chain within Australia.
"We should build on this, not sign a treaty mandating it out of existence."
Mr Briggs cast doubt Australia would receive submarines from the US on time, pointing to it falling behind in building its fleet.
Bernard Philip from the Department of Defence said advice was being provided to the federal government on extending the life of Australia's ageing Collins-class fleet.
The Pentagon has been investigating the AUKUS pact to ensure it aligns with President Donald Trump's "America-first" agenda.
The review by Under Secretary of War for Policy Elbridge Colby sparked speculation Mr Trump could walk away from the deal, which is estimated to cost up to $368 billion across 30 years.
Nikkei Asia on Tuesday reported the US would not make changes, with an unnamed member country official declaring AUKUS was "safe".
Mikaela James from the Australian Submarine Agency strongly hinted the US would not walk away from the deal.
"(We're) obviously aware of the US review that is under way and we are confident the US will continue to find that the program is in line with its interests," she told the committee.
The review is expected to finish before Prime Minister Anthony Albanese's visit to the White House on October 20.
Tim Deere-Jones, who has 40 years of experience researching the UK government's system for monitoring marine radioactivity, said managing nuclear waste was expensive and caused environmental issues.
"You've got to build the facilities to remove it out of the boats," he said.
"Then you've got to be looking for a long-term, hopefully perpetual dump site for it, none of which we've managed to do in the UK despite having many decades of nuclear submarines."
It was inevitable some waste would be discharged into the ocean, he said.
Nationals MP Alison Penfold said such concerns had the potential to undermine public confidence in AUKUS.
No sites have been identified to store and dispose of radioactive waste generated by Australia's nuclear-powered submarines, but options are limited to current and future defence estates.
Ms James said the sites would not be required until the 2050s, when Australia's first nuclear submarines were expected to be decommissioned.
Public information sessions were held in Western Australia in September and the submarines agency has "social licence teams" to ensure "accurate information is in the public domain", she said.
Building and maintenance contractor Serco has backed AUKUS but called for a visa clearance system to ensure workers could be mobilised quickly to deliver the nuclear submarines.
"What is needed now is a way to quickly muster expertise, transfer skills and build sovereign capacity," its director of people and capability Lucie Hannon said.