A fresh round of Coalition infighting has broken out, with Defence Minister Marise Payne sharply rebuking Tony Abbott for suggesting Australia should consider buying nuclear-powered submarines.
And Labor has played down Mr Abbott's suggestion the opposition could offer bipartisan support for a nuclear submarines program, arguing such a move was unrealistic.
While giving another speech, this time critiquing Australia's shipbuilding program, the former PM says we should consider nuclear submarines, also revealing his biggest regret while in the top job.
In his second major intervention into policy debate this week - which again placed him at odds with Turnbull government policy - Mr Abbott said Australia should consider acquiring nuclear-powered vessels from the United States, Britain or France.
The Turnbull government announced in April 2016 it would acquire 12 conventionally-powered submarines at a cost of $50 billion from French company DCNS. The boats are based on a French nuclear submarine, but will be redesigned to allow for diesel-electric propulsion, and are not expected to enter service until the 2030s
Senator Payne slapped down Mr Abbott's call to reshape its program, suggesting it was hypocritical and the Turnbull government's decision to go with DCNS delivered on the Abbott government's so-called Competitive Evaluation Process to purchase submarines.
"The process delivered exactly what the Abbott government intended and that is exactly what the Turnbull government is now delivering," she said.
"Australia currently lacks the qualified personnel, experience, infrastructure, training facilities and regulatory systems required to design, construct, operate and maintain a fleet of nuclear-powered submarines."
The usually media-shy Senator Payne is a leading Liberal moderate and her decision to fire back at the former prime minister underscores the tensions between the moderate and conservative wing of the government, which re-ignited this week over same-sex marriage.
Earlier, Mr Abbott had told the Centre for Independent Studies in Sydney that "not more robustly challenging the nuclear 'no-go' mindset is probably the biggest regret I have from my time as PM".
"The US already provides Australia with its most advanced aircraft and tanks and its most sophisticated submarine torpedo weapons system," he said. "We have nothing to lose from starting a discussion on this issue with our allies and friends – Britain and France – as well as primarily with the US."
Mr Abbott had suggested the nuclear-powered submarines could initially be based at the US base in Guam while Australia built up its domestic nuclear skills, currently limited to the Lucas Heights reactor in Sydney, over about 15 years.
Senator Payne said developing the domestic capacity to service nuclear submarines would take "far longer than a decade" and, in the short term, there were significant disadvantages.
"The advantages of acquiring nuclear-powered submarines would be lost without the capacity to sustain them in Australia, particularly if we were required to support the submarines in Hawaii or Guam, noting [the] time required to reach and return from these locations for maintenance."
Mr Abbott's suggestion Labor could offer its bipartisan support for the idea received short shrift from opposition defence spokesman Richard Marles.
"Labor is committed to an Australian build of the submarines in South Australia," he said. "Given we dragged the Liberals to this position, providing bipartisanship around this is our focus. Australia doesn't have a domestic nuclear industry so this just isn't realistic."
The Turnbull government has already privately discussed converting the Shortfin Barracuda into a nuclear-powered vessel in the future, but experts have warned it could take up to 15 years to have the domestic capacity to service the vessels.
Mr Abbott pointed out Indonesia, Singapore, India and Vietnam are expanding their submarine fleets, South Korea has 14 vessels already and Japan 19 vessels, while Russia and China's Pacific fleets dwarf Australia's and include nuclear-powered boats.
"Our new subs are supposed to be "regionally superior" – including, presumably, to the sharply increasing numbers of nuclear-powered attack submarines that are based in our region," he said.