Australia's "optimal" nuclear submarine pathway has started "to take shape" a year after the historic AUKUS plan was unveiled, but the government has so far refused to be drawn on any cost estimates for the massive project.
Defence Minister Richard Marles indicated Australia's future fleet would not involve a bespoke design or "orphan" class, but rather a nuclear boat also used by one of the AUKUS partners.
"Obviously, it is desirable that the submarine we ultimately operate is also operated by another country," Mr Marles said in an interview marking the one-year anniversary of the strategic partnership with the United Kingdom and United States.
"In that way, there is a shared experience in operating the platform, there's also a shared industrial base in maintaining and sustaining it, so that is a key consideration in the decisions that we are making."
Exactly one year ago, then-prime minister Scott Morrison made the shock announcement that Australia was dumping a $90 billion conventionally powered submarine program with France in favour of a nuclear option with help from the UK and US.
After unveiling the historic AUKUS partnership, Mr Morrison announced a newly formed Nuclear Powered Submarine Task Force would begin an 18-month study of British and American submarine technology to help identify Australia's best options.
Vice Admiral Jonathan Mead, who heads the task force, insisted AUKUS was "truly a trilateral partnership".
"In the 12 months since the announcement of AUKUS, the resolve of Australia, the UK and the US has only strengthened as the strategic environment has continued to deteriorate," he said.
Around 50 officials from the UK and the US are in Australia as part of twin AUKUS delegations for talks with Vice Admiral Mead and his task force.
"We have a shared mission, further confirmed by a very significant delegation here in Australia this week from the UK and US," he said.
"We continue our work together towards the decisions that need to be made as part of the optimal pathway for the acquisition of nuclear-powered submarines."
A recently released but highly redacted "Incoming Government Brief" prepared by the Defence Department confirmed Australia was still preparing to "transition to nuclear-powered submarines in the late 2030s".
British Defence Secretary Ben Wallace said earlier this month that the "ultimate" aim of the AUKUS partnership was "to get all of us to get through the 2030s where we produce a submarine that is, in my view, truly collaborative".
Cost of nuclear submarines, funding options unknown
Some experts have warned the eventual price of the AUKUS submarine fleet could be double the $90 billion price tag for the now scrapped French Attack-class submarine project, but the Defence Minister would not be drawn on cost estimates.
"Cost is obviously a factor here: we will be in a position when we make our announcements next year in relation to the platform to give a sense of cost that goes with it," he said.
Analyst Marcus Hellyer from the Australian Strategic Policy Institute believes the government will soon have to reveal whether Defence will get more funding, or which other military projects are facing cuts to help pay for nuclear submarines.
"One of the really big questions that at least everyone in Defence is thinking is will it get supplementation and that's another one of those really big unanswered questions at this point," he said.
