Peter Dutton has backed in AUKUS while pledging to ensure the partnership succeeds, as critics urge Australia to change course on its plans.
The support comes after former Liberal prime minister Malcolm Turnbull said Australia had no guarantee it would get the promised nuclear-powered submarines as the sale must not degrade the undersea capabilities of the US Navy.
"The most likely outcome of the AUKUS pillar one is that we will end up with no submarines of our own," he said while speaking at Parliament House on Monday.
"There will be Australian sailors serving on US submarines, and we'll provide them with a base in Western Australia.
"We will have lost both sovereignty and security and a lot of money as well. That's why I say it is a really bad deal."
Mr Dutton said he believed strongly in the AUKUS defence agreement and praised Anthony Albanese as then opposition leader for the bipartisan support.
"The need for AUKUS is greater than ever," the opposition leader said in Melbourne.
"Anyone who objectively looks at the deal that we've struck with the United States and the United Kingdom sees a capability that will underpin our security for the next century.
"As the prime minister points out, we live in the most precarious period since the Second World War ... they're saying that we want to see AUKUS succeed and we are absolutely dedicated to making that the case."
Asked about reports US President Donald Trump supported the AUKUS partnership, Mr Turnbull said "of course he'd like it".
"It's such a bad deal for us ... (Mr Trump) might be thinking, 'who are these dumb guys that agreed to this deal'?"
US Defence Secretary Pete Hegseth in February said the president supported the $368 billion deal after Australia made an $800 million downpayment for the plan to acquire nuclear-powered submarines.
Under the trilateral agreement with the US and UK, Australia has been promised at least three Virginia-class submarines from the US in the early 2030s, before a new fleet of boats is built for delivery from the 2040s.
Senior US military officers have described the partnership as "ironclad".
But Mr Trump's pick for defence policy under-secretary, Elbridge Colby, has previously questioned selling submarines to Australia because it could leave the US Navy "vulnerable" if there was military conflict with China.
A grassroots anti-AUKUS movement called Labor Against War has written to federal Labor MPs and candidates urging them to jump ship "given the tremendous upheaval in US-Australian relations in recent days and weeks".
Former Labor senator and campaign patron Doug Cameron said persisting with AUKUS would detract from the "many achievements of Labor in office and strengthen those who would profit at the expense of peace and diplomacy".
"The first few weeks of Trump’s presidency demonstrates he is belligerent, untrustworthy and dangerous," he said.
"There are other more realistic and cost-effective strategies to protect our territorial integrity without subjugating ourselves to a dangerous, unpredictable and unworthy Trump administration."
