Australia and US should 'match' defence capabilities

Australia and the US need to ensure both nations' military capabilities "match," War Secretary Pete Hegseth has told high-level talks.

Defence Minister Richard Marles met with his US counterpart in Washington to discuss key priorities and progress on AUKUS.

Australia has been promised nuclear-powered submarines under the pact.

As the two allies marked the 75th anniversary of the ANZUS treaty, Mr Hegseth spoke about the need to "ensure our capabilities match and are complementary".

He has previously pressured Mr Marles for the government to lift defence spending.

Mr Marles said Australia came to the US with a "good story" to tell on expenditure.

"We now have defence spending at 2.8 per cent of GDP by the NATO measure, puts us ahead of most NATO countries," he told reporters on Thursday.

"This is the biggest peacetime increase in defence spending that we've done ... we understand the American position, but I think that is a story which is well received here."

An independent public inquiry into AUKUS has been told Australia should have stuck with the previous French submarine deal scrapped in favour of the security pact.

Former senior naval officer Peter Briggs criticised the lack of debate within Defence on the issue.

"The so-called optimal pathway, designed I think by some political aides in a coffee shop, certainly no one who's ever been anywhere near sustaining and operating a submarine had any detailed involvement in this grand plan," he told the inquiry.

Greens senator David Shoebridge said Australia is making "a criminally reckless gamble" to further align itself with the US.

"We are literally structuring our entire defence force to not be independent but to literally be an interoperable cog with another country," he said.

"It makes us more dangerous aligning with the United States, and it comes with an obscene financial cost."