President Joe Biden has arrived in South Korea on his first Asia trip as US leader, aiming to cement economic and security ties with regional allies despite growing fears of a North Korean nuclear test.

His first stop on Friday was a massive Samsung semiconductor factory, where he received a warm welcome from South Korea's new President Yoon Suk-yeol, with global supply chain issues topping the agenda.

Biden, in his first remarks since arriving in South Korea at the start of a trip meant to demonstrate US resolve to lead in Asia, said the two countries' alliance was "a lynchpin of peace, stability and prosperity" in the world.

US President Joe Biden is headed to Asia for the first time since taking over the White House US President Joe Biden is headed to Asia for the first time since taking over the White House Photo: AFP / ROBERTO SCHMIDT

Speaking at the factory in Pyeongtaek alongside Yoon, Biden described the advanced semiconductors manufactured there as "a wonder of innovation" and crucial to the global economy.

The tiny, smart wafers "enable our modern lives" and are "the key to propelling us into the next era of humanity's technological development", he added.

Semiconductors -- the microchips essential to most modern devices from phones to cars and high-tech weapons -- are at the heart of a global supply chain slowdown that threatens to disrupt the world's post-Covid economic recovery.

South Korea and the United States need to work to "keep our supply chains resilient, reliable and secure", Biden said.

Joe Biden, flanked by Sweden's Prime Minister Magdalena Andersson and Finland’s President Sauli Niinisto, at the White House on May 19, 2022 -- the US gave its full support for Sweden and Finland's bids to join NATO Joe Biden, flanked by Sweden's Prime Minister Magdalena Andersson and Finland’s President Sauli Niinisto, at the White House on May 19, 2022 -- the US gave its full support for Sweden and Finland's bids to join NATO Photo: AFP / MANDEL NGAN

"Putin's brutal, unprovoked war in Ukraine has further spotlighted the need to secure our critical supply chain," he said.

The United States needs to ensure "our economic and our national security are not dependent on countries that don't share our values," he added.

Biden and Yoon are to hold talks and give a press conference in Seoul on Saturday before attending a state dinner.

Map and factfile on North Korea's nuclear tests Map and factfile on North Korea's nuclear tests Photo: AFP / STAFF

For the US leader, whose Democratic Party fears a possible trouncing in midterm elections in November, the issue is also an acute domestic political challenge, with Americans increasingly frustrated over rising prices and stuttering economic reopening.

Ahead of the speech, Biden toured the huge Samsung plant, taking in lengthy presentations from staff clad in hazmat suits on the equipment used to produce semiconductors.

US President Joe Biden speaks alongside South Korean President Yoon Suk-yeol (center-L) -- the pair will hold talks in Seoul as part of Biden's visit to South Korea US President Joe Biden speaks alongside South Korean President Yoon Suk-yeol (center-L) -- the pair will hold talks in Seoul as part of Biden's visit to South Korea Photo: AFP / SAUL LOEB

After a briefing from a US representative from a California company working with Samsung, Biden quipped: "Don't forget to vote, Peter".

Samsung employs about 20,000 people within the United States and work is underway to build a new semiconductor plant in Texas, opening in 2024.

South Korea is a semiconductor powerhouse, supplying about 70 percent of chips globally, Yoon said in his speech, asking Biden to take a "special interest" in South Korean chip firms.

US President Joe Biden (L) stands next to South Korean President Yoon Suk-yeol (2L) during their visit to the Samsung plant US President Joe Biden (L) stands next to South Korean President Yoon Suk-yeol (2L) during their visit to the Samsung plant Photo: POOL via AFP / KIM Min-Hee

Biden's visit could help the two allies forge a new "economic and security alliance based on advanced technology and supply-chain cooperation", Yoon said.

Semiconductors are now "something akin to a strategic commodity", Vladimir Tikhonov, professor of Korean studies at the University of Oslo, told AFP.

China is trying to reduce reliance on US-influenced Dutch and Taiwanese suppliers, and the United States is trying to rebuild its domestic industry, he said.

Biden "needs Samsung's collaboration in this regard", he added.

Biden wants the trip to boost a years-long US pivot to Asia, where rising Chinese commercial and military power is undercutting Washington's dominance -- but it risks being overshadowed by North Korea's nuclear ambitions.

"We remain concerned that the DPRK may attempt to undertake another provocation during the course of the president's visit to Northeast Asia or in the days following," State Department spokesman Ned Price said in Washington, referring to North Korea by its official acronym.

South Korean intelligence has warned that Pyongyang had recently completed preparations for a nuclear test, while Price said another possibility was a new launch of an intercontinental missile.

Security issues were not top of the agenda Friday, but the fact that Biden is visiting Seoul first on his Asia tour indicates that Washington is looking to refocus on the Korean Peninsula, former CIA analyst Soo Kim told AFP.

"Should Kim proceed with a test during Biden's visit, he will effectively be helping the two countries find greater justification to work together on the North Korea issue," she said.

Biden heads to Japan from South Korea on Sunday. He will also join a regional summit of the Quad -- a grouping of Australia, India, Japan and the United States -- while in Tokyo.

Even so, the whole point of Biden's Asia tour is China, Katharine Moon, a political science professor at Wellesley College, told AFP.

"It's an effort to strengthen economic and security relationships with the Asia-Pacific region and block China's growing influence," she said.

National Security Advisor Jake Sullivan said the aim of the trip is not to confront China, but to highlight that the West and its Asian partners will not be divided and weakened.

But China said Friday that the United States should "build an open and inclusive circle of friends in the Asia-Pacific, instead of assembling closed and exclusive small cliques."