The federal government unveiled a $12 billion investment in the Henderson Defence Precinct in Perth, where the nuclear submarines Australia will acquire under the pact will be able to dock.
US submarines would also be able to undergo maintenance at the facilities.
Uncertainty still clouds the $386 billion AUKUS deal, with the US undertaking a review as the Trump administration pushes its allies to increase defence spending to 3.5 per cent of gross domestic product.
Defence Minister Richard Marles said the defence capability boost was about increasing Australia's capabilities, and not just satisfying the US.
"It's also going to be the basis upon which we sustain and maintain our future submarines, and that is critically important for the country," he told Nine's Today program on Monday.
"What we're focusing on is the actual dollars that you spend on defence, and we've been making that clear."
Australia's defence spend as a share of GDP is about two per cent, with the government pledging to increase it to 2.3 per cent by 2033/34.
However, under a definition of defence spending by NATO, which also includes defence infrastructure, Australia's spend is 2.8 per cent, Mr Marles argued.
"We've never been focused on what percentage of GDP. We have always articulated this in the context of the dollars that we are spending," the defence minister said.
"We have dramatically increased Australia's defence spending over the course of the last three years.
"It is the biggest peacetime increase in Australia's defence spending in Australia's history."
Under the AUKUS deal, Australia will acquire three nuclear-powered Virginia-class submarines from the US in the early 2030s before a new fleet of boats is built for delivery from the 2040s.
Opposition defence spokesman Angus Taylor said the naval boost was welcome, but more needed to be spent on Australia's defence.
"It's not going to touch the sides of what's necessary in terms of creating a fit-for-purpose defence force, at a time which is more dangerous than any time since the Second World War," he told ABC Radio.
"We need to see defence get to three per cent of GDP - that's about an extra $25 billion a year currently in spending."
The coalition went to the last federal election pledging to lift defence spending to three per cent.
While Mr Taylor did not say how the coalition would fund the increase, a boost to defence was still needed.
"If this government is underfunding defence, you can expect scepticism from our most important ally, the United States, that has underpinned peace in our region."
Prime Minister Anthony Albanese could meet US President Donald Trump later this month on the sidelines of the United Nations General Assembly meeting and will likely seek assurances about the future of the AUKUS trilateral defence agreement.
Former Australian Ambassador to the United States Arthur Sinodinos noted the significance of announcing the boost ahead of a possible meeting with Mr Trump.
"The timing would be, I think, pitched to lay the groundwork and have something to put on the table with the president," he told AAP.
In return, Mr Albanese would be seeking assurances from the president about his support for AUKUS, Mr Sinodinos said.
"While we had indications of support from others in the administration, it's important for the prime minister to hear it directly from the president," he said.
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