Indo-Pacific region is at the core of long-term United States foreign policy despite concerns over Russian aggression toward Ukraine, United States Secretary of State Antony Blinken said on Thursday.

Blinken is in Melbourne for a meeting on Friday with his counterparts from Australia, India and Japan.

The four nations form the so-called "Quad," a bloc of Indo-Pacific democracies that was created to counter China’s regional influence.

"There are a few other things going on in the world right now, some of you may have noticed. We have a bit of a challenge with Ukraine and Russian aggression. We’re working 24/7 on that,” Blinken said in his first public address since arriving in Australia on Wednesday.

"But we know, the president knows better than anyone else, that so much of this century is going to be shaped by what happens here in the Indo-Pacific region,” he added.

The Indo-Pacific is the fastest-growing region in the world, accounting for two-thirds of global economic growth over the past five years and home to half the world’s population, Blinken said.

What matters in the region matters around the world and challenges like climate change and COVID-19 can’t be tackled by any nation alone, he said.

"More than ever before, we need partnerships, we need alliances, we need coalitions of countries willing to put their efforts, their resources, their minds into tackling these problems,” Blinken said.

"What really drives us is a shared vision" of a "free and open society," he added.

Blinken’s trip is designed to reinforce America’s interests in Asia and its intent to push back against increasing Chinese assertiveness in the region. He will also visit Fiji and discuss pressing concerns about North Korea with his Japanese and South Korean counterparts in Hawaii.

Australian Foreign Minister Marise Payne, who will chair the Quad meeting, said the agenda would include COVID-19 vaccine distribution, cyber and critical technologies, countering malicious and dangerous disinformation, terrorism, maritime security and climate change. India will be represented by External Affairs Minister S. Jaishankar and Japan by Foreign Minister Hayashi Yoshimasa.

"As a network of liberal democracies, we are committed to very practical cooperation and ensuring that all Indo-Pacific nations – large and small – are able to make their own strategic decisions and make those decisions free from coercion,” Payne said.

In Beijing on Wednesday, Foreign Ministry spokesperson Zhao Lijian responded to a question about Blinken’s visit with a lengthy attack on American democracy and an explanation of China’s contributions to the global order.

"With its so-called democracy having collapsed long ago, the U.S. is forcing other countries to accept the standards of the American democracy, drawing lines with democratic values and piecing together cliques. That is a complete betrayal of democracy,” Zhao told reporters.

Blinken is expected to address threats posed by a growing partnership between authoritarian Russia and China, particularly after the Sunday meeting in Beijing between Russian President Vladimir Putin and Chinese leader Xi Jinping at the opening of the Winter Olympics.

The U.S. had hoped that the Xi-Putin meeting would have demonstrated Chinese wariness about Russia’s military buildup along Ukraine’s borders. But Xi was largely silent on the matter.

Australian Defense Minister Peter Dutton expressed concern over the Russian-Chinese alliance and said the threat posed by China was growing.

"We know that our nation is facing the most complex and potentially catastrophic regional security environment since the Second World War,” Dutton told Parliament on Thursday.

Blinken has a family link to Melbourne through his stepfather Samuel Pisar, a lawyer and U.S. presidential adviser who died in 2015.

Polish-born Pisar was orphaned during World War II and sent by an aunt to Melbourne where he was cared for by two uncles who had immigrated in the 1930s.

Blinken on Thursday visited the Melbourne Law School where Pisar had excelled before moving to the United States to continue his studies at Harvard University.