Richard Marles, who is also currently the acting Prime Minister, flagged possible easing in defence industry export controls as part of the discussions with the UK and United States towards a "seamless" defence industrial base across the three countries.

"There is appropriate regulation in all countries around how defence industry operates, but we really do need to break down some of those barriers if we're going to advance at the pace that we need to, and we hope that AUKUS can do that," Mr Marles told Insiders on Sunday.

Those controls are chiefly imposed by the US and have limited the growth of Australia's defence industry. But there are also other barriers that local firms say make it more difficult to get innovative technology into defence in Australia than overseas militaries.

Mr Marles clarified comments made in the US several months ago that the relationship between their militaries were moving beyond interoperability to interchangeability. He said that was not about giving up control of Australia's assets in operations, or sovereignty of its forces.

"It might mean that we're using common artillery, that we're using common ammunition which can be used across different platforms," he said.

"It gives rise to a much more integrated set of defence forces that can operate in a much more interoperable and much more interchangeable way - that means that we're more nimble and more potent as a result."

Last week for the first anniversary of AUKUS, Mr Marles said an "optimal pathway" was emerging for Australia to develop the on-shore capability to build nuclear-powered submarines, except for the nuclear reactor itself, sooner rather than later.

More would be revealed in March, he said, such as the design choice for the submarine fleet. However, Defence experts have largely dismissed Australia adopting the UK's 'Astute' design, in favour of the US 'Virginia' class design, or a new common submarine design for all three militaries.

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Australia was not just picking a design, says ASPI's senior analyst Marcus Hellyer from the government-funded strategic think tank - it was picking a strategic partner.

"I don't think too many people are going to would be surprised if it's the US," Dr Hellyer said. "If it's the US, you're picking your strategic partner as a nation with the greatest ability, the greatest capacity to assist us.

"Until you pick your strategic partner, you can't really know the industrial strategy because you don't know what you can rely on them to do, and what we're going to have to do ourselves."

Those choices would also determine the schedule, and what interim capabilities Australia would have to pursue to fill the gap until the new submarines come online. The UK may play a role, but it was unlikely to have the industrial capacity to help Australia to the degree that it needed, he said.

"What we're learning is that [rather than] primarily a choice between the Astute class and the Virginia class, that it's all about just picking a submarine, we're learning that it is much more complicated than that.

"The design sort of falls out at some of the higher-level issues such as, who's your strategic partner, what's your industrial strategy, what's your appetite for risk in the transition?"