"The United States has no closer and more reliable ally," Biden told Morrison on the sidelines of the UN General Assembly in New York.

Biden said their countries were committed to a "free and open Indo-Pacific" -- code for the US-led push to contain the rising power of China.

He noted that they would meet again Friday in the White House at the first in-person session of leaders from the Quad group -- Australia, India, Japan and the United States -- which is likewise dedicated to preserving stability in the Indo-Pacific.

"It's a historic meeting and I think we're all looking forward to it," Biden said.

The US president, who earlier told the United Nations that Washington is focusing on alliance building and diplomacy after ending the failed 20-year war in Afghanistan, said the geopolitical situation requires watching carefully.

"The United States and Australia are working in lockstep," he said. "Democracy and setting the rules of the road for the 21st century -- I mean what I said: we are at an inflection point. Things are changing."

Morrison stressed his country's "more than 100 years of our partnership where we have stood together through the most difficult times and the most prosperous times."

But he also underlined that this was not an exclusive relationship and that US-Australian values are shared with "so many others."

The two leaders made no mention of France's continuing fury over losing a contract to sell Australia conventional submarines in the wake of a decision by Morrison's government to work with the United States on building a fleet of nuclear-powered submarines.

The US-Australian deal also involves Britain in a new security pact dubbed AUKUS. France recalled its ambassadors from both the United States and Australia to underline its displeasure.