Anthony Albanese has had "warm and engaging" talks with the outgoing US president, exchanging gifts with Joe Biden at his personal home ahead of a summit focusing on strategic partnerships in the Indo-Pacific region.
The prime minister is in the US state of Delaware for the fourth in-person meeting of the Quad with leaders of the US, Japan and India.
The summit may be a "final victory lap" for Mr Biden but Australia will still have a crucial role to play, experts say.
While security and stability in the Indo-Pacific will dominate discussions, the summit will be the last attended by the outgoing US president.
Mr Albanese said it was a privilege to spend time with Mr Biden on Friday evening, local time, ahead of a meeting of the Quad leaders.
"It was a very warm and engaging discussion ... a discussion between allies and a discussion between friends," Mr Albanese told reporters.
"My understanding is it was the first time that a foreign leader has met him at his home, and so I feel that it was a great honour," he said.
The pair exchanged gifts - a leather air force jacket for Mr Biden, and for the prime minister a book on the Catholic high school the president attended - where the pair will meet with Indian Prime Minister Narendra Modi and Japanese Prime Minister Fumio Kishida on Saturday, local time.
Defence and security co-operation in the Indo-Pacific and the AUKUS partnership, including Australia's progress towards a fleet of nuclear-powered submarines, were discussed during the 90-minute meeting, ahead of the November US presidential election.
Mr Albanese said there was deep support across the political spectrum for the partnership.
"There is no question in my mind that AUKUS will continue to have the support of any future US administration," he said.
Economic issues including inflation and supply chains were also canvassed along with climate action and clean energy.
The pair also discussed ongoing conflicts in Ukraine and the Middle East.
Regional challenges will be the focus of further discussions during the Quad meeting.
The Quad had brought a united front to the region despite the perception it had not delivered tangible results, the Lowy Institute's Southeast Asia Program director Susannah Patton said.
"The Quad in many ways is the centrepiece of the Biden administration's Indo-Pacific strategy, so it's important to the US they do this final victory lap and finish on a high note," she told AAP.
While Australia may be the smallest of the Quad nations, Ms Patton said it would have a critical role given its proximity to Pacific nations and China.
The upcoming Quad meeting would not differ greatly from previous summits but it was important the group demonstrate real outcomes, United States Studies Centre research fellow Tom Corben said.
"The stock placed in the Quad as a bellwether of US strategy in Asia can be overstated," he told AAP.
"It is now beyond the point for flashy statements and it's time for concrete action."
Mr Biden dropped out of the presidential race, endorsing his vice-president Kamala Harris in July, amid criticism of his age and concerns for his health as he sought another four-year term.
Mr Albanese said it was an engaging meeting with the 81-year-old US politician.
"He's fit, he is totally on top of his brief, he is someone who it's a great privilege to spend time with," Mr Albanese said.
