A senior Albanese Government minister has confirmed the US recently changed its mind over which Virginia-class submarines should be transferred to Australia under AUKUS — but insists the new approach is what this country always wanted.

New details are emerging about which second-hand boats Australia will be buying from the US as the Government scrambles to clean up what appeared to be a surprise recent announcement on a changed approach to the AUKUS “optimal pathway”.

Defence Minister Richard Marles and his American counterpart Pete Hegseth announced in Singapore at the weekend that Australia will now be acquiring three “in service” Virginia-class submarines starting in 2032, rather than two second-hand and one brand-new boat.

Australia’s new Defence secretary Meghan Quinn on Tuesday night claimed buying only second-hand submarines was always the preference for AUKUS, before later clarifying to a Senate committee that the project could have “two constrained optimal pathways”.

Discussions around which type of submarines Australia would buy ramped up in the weeks before Mr Marles and Mr Hegseth met on the sidelines of the Shangri-la Dialogue, The West understands, but details about the change weren’t foreshadowed.

Defence Industry Minister Pat Conroy said on Wednesday that Washington had changed its mind about what mixture of submarines they wanted in their fleet and re-examined the arrangement.

“This is better for us, and that’s why we asked for it originally,” he told The Nightly.

“This is the US administration making another active decision to confirm AUKUS by saying yes, we think it’s better that you get three in-service subs, it’ll be cheaper to run, cheaper to maintain and simpler.”

Treasurer Jim Chalmers said the change would save Australia money, but how much will remain secret until the next Budget update, not expected until December.

“This will make the investment a bit cheaper, but we don’t update that from week to week. We do that from budget to budget and you can expect us to do that at the next opportunity,” he said.

Notes taken by this masthead on a briefing about the optimal pathway when the detailed AUKUS deal was announced in San Diego in March 2023 show that, at that time, it was “still to be resolved whether (the) Virginias are second-hand or new”.

Separate contemporaneous notes from the same briefing recorded that there would be “three, possibly second-hand, Virginias sold to Australia”.

By November 2023, senior US Navy officer Vice Admiral Bill Houston was saying the arrangement would be to sell two in-service and one brand-new submarines to Australia.

Mr Conroy said Australia had consistently been pushing to get three boats that had been through their first significant maintenance.

“This is not like getting a new Tesla. Getting a brand-new Virginia is like getting the first Tesla ever made — it’s going to have problems,” he said.

“Every new platform has running issues that you have to resolve, and you can spend years doing that. So by getting all three subs six or seven years in, after their first major maintenance period, the US Navy’s taking the risk with them, they’ve ironed out all the kinks, and we’re getting them at their peak operating efficiency.”

Shadow defence minister James Paterson said there were legitimate arguments to make that running three of the same type of Virginia-class submarines was simpler, but that the Government hadn’t given a full explanation of why the change was necessary.

“The government won’t explain how much cheaper it will be. Officials have no answers at all about the specifics, despite the fact that the Defence Minister has claimed it would significantly cheaper,” he said after quizzing department officials during Senate estimates.

“The optimal pathway was actually chosen by this government, by the Albanese government in 2023. This is their plan, which they are now changing.”

Asked whether the announcement made by his colleague Richard Marles over the weekend was not handled well, Mr Conroy told The Nightly: “I think it was handled well, I’m just providing more detail, which is my job.”

The Virginia-class submarines have an estimated lifetime of 33 years, and Australia has been assured that it will receive ones that have only just been through their first maintenance, with 25-27 years remaining.

That means the first one, due to be acquired in 2032, will be a submarine rolling off the production line this year.

The two defence establishments are now in the process of identifying exactly which boats Australia will receive.

Ms Quinn told Senate estimates late on Tuesday night that the decision about whether Australia would buy new or old boats was “a joint discussion with the United States”.

Senator Paterson pressed her on whether the United States had originally “imposed a new submarine on us and said: you must take a new submarine even if you want three in-service”.

“The joint decision at that time was that there would be two in-service and one new, there were discussions at that time around the different options and at that time the joint discussion was to have two in-service and one new,” she replied.

The exchange came just hours after outspoken Labor MP Ed Husic challenged the Prime Minister to allow caucus members to have a fresh vote on AUKUS following the changes unveiled over the weekend.

Mr Marles, who was returning from his talks with Mr Hegseth and missed the caucus meeting, said that “obviously Ed is very much entitled to his opinion” but the government was “unambiguously supportive” of AUKUS.

“There is a change in terms of the third of the Virginia classes going from being what had been intended to be a new submarine to being an in-service submarine. We’re talking about a single submarine,” he told a Defence industry conference after arriving back in Canberra.

“I mean, the first two were always going to be in service. Nothing’s changed about that. And the bulk of AUKUS actually is the building of our own submarines in Adelaide and nothing is changing there.

“So, in the context of the bigger picture here, this is not a huge part of it. You wouldn’t describe it as fundamental.”