Outspoken Labor backbencher Ed Husic has urged the Prime Minister to give government MPs a new vote on the AUKUS agreement following recent changes to the $368 billion deal revealed by Defence Minister Richard Marles.

Over the weekend Mr Marles confirmed Australia would now receive three used Virginia-class submarines from the United States instead of one new and two second-hand boats, arguing the move would improve simplicity and be significantly cheaper.

Critics have labelled the adjustment to the AUKUS “optimal pathway” as a slap in the face for Australia driven by Pentagon AUKUS-sceptic Elbridge Colby.

Under the AUKUS plan Australia is scheduled to receive at least three Virginia-class boats from the US in the 2030s before eventually transitioning to a new fleet of known as SSN-AUKUS in the 2040s that are being produced in collaboration with the UK.

Ed Husic, who was the industry minister last term but was dumped to the backbench by Mr Marles, has questioned whether the original caucus decision backing in the push to acquire nuclear-powered submarines still stood given the latest changes.

Speaking to reporters after a Labor caucus meeting on Tuesday, Mr Husic said concerns over the slow submarine production rate in the United States meant it was time for parliamentary members of the party to have another say on the AUKUS deal.

“You got support for the deal as it was structured back then, but that deal versus what we’ve got now are different, and I think that it now gives us a moment to think about whether or not the deal should be reconfigured, or what are the contingencies on that”.

“I’ve raised my concerns. I think there are broader concerns around if you look at the transactional nature of the Trump administration and them no doubt having expectation if they did this deal with us, what they would expect us to be using those subs for.”

“This deal has changed, and as a result, we need to recognise — is there anything that is going to improve this outcome or alter it? I don’t think so,” Mr Husic said.

“There’s obviously been — this is a great understatement — but you’ve seen within the broader [Labor] movement a general disquiet about the nature of the deal itself.

During the caucus meeting, Prime Minister Anthony Albanese replied that it had always been the plan for Australia to get some used submarines from the US and that AUKUS “is a solid and good arrangement”.

Defence Industry Minister Pat Conroy also told caucus that the new arrangement would be easier to manage and more cost-effective than getting two different types of Virginia-class subs from the US, an argument that Mr Marles has also mounted.

Mr Conroy explained to colleagues that ultimately the difference for retirement timing of a used submarine compared with a new one was a question of whether the third boat reached the end of its life in the 2060s or in 2070.

Asked whether the government could rethink its support for AUKUS after breaking promises on tax, Treasurer Jim Chalmers insisted the government supported the current arrangements, and he wouldn’t “get into the details of discussions in the parliamentary party.”

Opposition spokesperson James Paterson has seized on Mr Husic’s comments, describing his intervention as “a full-on Labor revolt when it comes to Australia’s signature defence policy, AUKUS.

“It’s a result of Labor’s mismanagement of the delivery of AUKUS. And Richard Marles’ failure, along with the Prime Minister, to make the case for AUKUS among Labor’s own supporters,” the shadow defence minister said.

Some commentators have played down the significance of the downgrade of submarines being transferred by the US, but experts have calculated that Australia will lose at least 8 years of deployable service under the new scenario, or possibly 16 years.

Sources familiar with AUKUS deliberations in Washington claim the latest changes were driven by the Pentagon over concerns Australia is not meeting its ‘sovereign ready’ milestones in time to demonstrate that it can operate nuclear-powered submarines.

Similar concerns were expressed publicly last week by a former US Navy Secretary who warned about Australia’s lack of “urgency” in preparations for AUKUS project and the slow progress on overhauling Western Australia’s Henderson shipyard.

Richard Spencer, who now serves as Chairman of Perth-based shipbuilder Austal, argued the government must appoint a powerful official to coordinate the complex nuclear-submarine endeavour, like celebrated US World War Two Admiral Rickover.

“We need this concept of a (Admiral) Rickover to be in Australia, someone who is just laser focussed on this program,” Mr Spencer told the Indian Ocean Defence and Security Conference (IODS) in Perth.

Other figures connected to the Pentagon have blamed US Under Secretary of War Elbridge Colby for running interference over AUKUS because of concerns about the slow pace of submarine production in the United States.

“This is Elbridge Colby doing what he’s always done — trying to throw sand in the gears of the whole AUKUS endeavour. He’s going to keep trying to take shots at it until he thinks he can sink it.”

Another figure connected to AUKUS planning work tells The Nightly that Elbridge Colby continues to cause problems with the project, but insists his influence is “far less” than it was previously.

Already Australia has transferred $US3 billion ($4.2b) to Washington to help double its submarine production rates ahead of the scheduled transfer of Virginia-class boats to this country in the 2030s.

Labor MPs have broadly backed the AUKUS initiative publicly since Mr Albanese agreed to the plan when it was announced at short notice by then-prime minister Scott Morrison in 2021.

After Labor won office in 2022, it began fine-tuning the AUKUS “optimal pathway” which initially involves rotations of US and UK nuclear-powered submarines out of HMAS Stirling naval base in Perth from next year.

In the next phase Australia is expected to buy between three and five Viriginia-class submarines before a new design, the SSN-AUKUS, is built both in Adelaide and the UK and is scheduled to enter service in the 2040s.

Greens Senator, and leading AUKUS critic, David Shoebridge has welcomed the renewed debate inside Labor saying the government should be asking questions about the security partnership.

“We’re not just over a barrel with the United States — we have literally said to them they can name the price, they can give us the biggest lemon in the fleet — three of them — and Richard Marles will give that blank cheque to the US,” he said.

The latest airing of concerns in caucus on Tuesday came at the same time former Labor minister Peter Garrett announced he would lead a national public inquiry into AUKUS, along with former Defence Force chief Chris Barrie.

“The AUKUS decision is the most momentous and expensive decision ever made by any Australian government in the modern era,” Mr Garrett told reporters standing alongside independent MP Andrew Wilkie.

“A public inquiry into this massive spend of taxpayer’s money is long overdue. It is a decision that asks all of us to fully understand the implications of what is contained in that decision.”

“And to provide the opportunity for Australians across the political spectrum, and all walks of life, to be heard and submit to a public discussion about this massive expenditure.”

Retired Admiral Barrie said that between 2004 and 2010, he and the then Defence Secretary Paul Barrett had explored the idea of acquiring nuclear-powered submarines, but concluded it wasn’t viable.

“Our idea was built on the notion that we would have a nuclear power industry on which to build engineering expertise, make us a smart buyer and deal with some of the issues that have already been raised in going forward with this project.”

“At the moment, what I see is we will not be a smart buyer. We haven’t solved some of the problems that would have had to be solved, but we could make no headway either in the UK or in the United States back in 2010 so now I ask myself, what’s changed?”

At the ALP national conference in 2023, Fremantle MP Josh Wilson led a backlash to AUKUS and spoke in Parliament to argue against the acquisition of nuclear-powered submarines.