A political stoush on national security has erupted just days before an expected announcement on the AUKUS submarine plan, with Peter Dutton warning against acquiring a future fleet from the UK.
The government has condemned the opposition leader's comments as "irresponsible" and "mischievous" and accused the former defence minister of undermining the nuclear-submarine program.
Recent speculation has suggested a developmental British submarine known as SSNR is emerging as a likely candidate for Australia's future nuclear-powered fleet.
During a visit to the Avalon Air Show in Victoria, Mr Dutton insisted American Virginia-class submarines remained the best and most practical option for Australia.
"The beauty in my mind with the American model, of the Virginia class, was that it was a proven design, it gave us interoperability with the Americans and there will be more American subs in the Indo-Pacific than there will be British submarines".
Mr Dutton said the advice he received as defence minister before last year's election was that the British companies involved in the UK's submarine production had no extra capacity to support an Australian program.
"The advice to me at the time was very clear: that Rolls-Royce didn't have any production capability left, no headroom; Barrow-in-Furness is obviously landlocked, it didn't have the ability to scale up".
Last year, Mr Dutton asserted that when he was defence minister he was confident of securing two American Viriginia-class nuclear submarines by 2030.
Defence Industry Minister Pat Conroy, who was also at Avalon to sign a deal with Boeing on Australian content for Apache helicopters, condemned Mr Dutton's latest remarks.
"I think those comments from Peter Dutton are incredibly irresponsible. This was a man who received classified briefings up until the 21st of May on this program," he said.
"I just find it completely unhelpful in the public debate for him to be injecting this stuff when he knows that there are security reasons that mean that we can't detail information until we make the announcement.
"He is either being mischievous or he isn't privy to the latest information."
In recent weeks Defence Minister Richard Marles has insisted that the looming AUKUS announcement on an "optimal pathway" would be a "truly trilateral" solution.
Prime Minister Anthony Albanese is this month expected to travel to Washington DC to unveil Australia's AUKUS plan alongside the US President Joe Biden and British Prime Minister Rishi Sunak.
Challenges with frigates
Mr Conroy also commented on the state of a $35-billion deal signed in 2018 with British company BAE to build Hunter-class frigates.
"This is a project that we inherited from the last government, a project where, quite frankly, the last government lied about what they were buying," he said.
"They presented to the Australian public that 'we are buying a proven off the shelf product that effectively all the kinks have been resolved'.
"Instead, we've got a developmental project, where the project cost has increased by 50 per cent to just under $45 billion, and we're facing delays of between two and four years on separate stages of it."
Mr Conroy said the government was committed to working with BAE and the Australian Navy to fix the project.
