Co-ordinator for Indo-Pacific Affairs on the US National Security Council Kurt Campbell instead said the trilateral deal would instead be "the most important strategic innovation" of the era.

Former prime minister Paul Keating last month likened the promised nuclear-powered submarines, touted to boost military capability against China's rising dominance in the region, as throwing "a handful of toothpicks at a mountain".

In a discussion with Lowy Institute executive director Michael Fullilove on Wednesday, Mr Campbell said the deal would strengthen the alliance and cooperability between the three nations in the Indo-Pacific region.

"You see a China that is more risk acceptant, more assertive, more determined to basically take steps that other countries would view as coercive and so I think that feature plays prominently," he said.

"I don't believe that Australia and Great Britain joining with the United States is some evidence of, you know, throwing in with an effort that is doomed to failure or ... strategically irrelevant. Far from it.

"I think this is going to be the most important strategic innovation of our ... of this period. And I think its significant and it sends a powerful message to every country involved."

Mr Keating told a press club lunch in November the government's "appalling" escalation of tensions with China, and its flawed nuclear submarine ambitions, were a shift in the wrong direction for the country, instead urging stronger engagement with the emerging global superpower.

"We are at odds with our geography and we have lost our way," he said.

He was also critical of the US for trying maintain strategic primacy in both the Atlantic and Pacific oceans simultaneously, rather than a switch to balancing and conciliating power in the latter region.

Australia had tied itself to the US's "wishful thinking" that it could be the security guarantor in two vast regions at once, he said.

But Mr Campbell said he disagreed with this interpretation, adding he believed China would ultimately be brought back to the table on diplomacy with Australia because deep down, it respected the strength, resilience and fortitude it demonstrated.

"I fully believe that over time, that China will re-engage with Australia but it will, I believe, re-engage on Australian terms," he said.

"I think Australia - China's preference would have been to break Australia. To drive Australia to its knees. And then you know, find a way forward. I don't believe that's going to be the way it's going to play out.

"I believe that China will engage because it is in its own interest to have a good relationship with Australia."

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While the nuclear technology sharing aspect of the AUKUS deal would remain between the three nations, Mr Campbell said, at Australia and the UK's insistence, other areas could be opened up to like-minded partners.

He said cyber was one area that would likely feature in any expanded deals.

"This is not a closed architecture. It's an open architecture," Mr Campbell said.

"We want to work with partners in these key areas of military innovation as we go forward.

"We've got time to design and to figure out what, where are the areas that have the most potential."