Biden to urge Xi to rein in North Korea in G20 talks

President Joe Biden will urge Chinese President Xi Jinping to restrain North Korea's "worst tendencies" and tell him that Pyongyang's arms build-up will prompt an "enhanced" US military presence in Asia, a senior official has said.

In a Monday meeting on the sidelines of the G20 summit, Biden will tell Xi that China has "an interest in playing a constructive role in restraining North Korea's worst tendencies," National Security Advisor Jake Sullivan told reporters on Saturday.

Biden will also tell Xi that if North Korea's missile and nuclear build-up "keeps going down this road, it will simply mean further enhanced American military and security presence in the region."

Sullivan, speaking aboard Air Force One en route to Cambodia for a regional ASEAN summit this weekend, said Biden would not make demands on China but rather give Xi "his perspective."

This is that "North Korea represents a threat not just to the United States, not just to (South Korea) and Japan but to peace and stability across the entire region."

Whether China wants to increase pressure on North Korea is "of course up to them," Sullivan said.

However, with North Korea expected to soon test a nuclear weapon and rapidly ramping up its missile capacities, "the operational situation is more acute in the current moment," Sullivan said.

Biden flies to Phnom Penh

Meanwhile, Biden touched down in Phnom Penh for meetings with Southeast Asian leaders ahead of his encounter with his Chinese counterpart on Monday in Bali.

The meeting between the two superpowers comes after a record-breaking spate of missile tests by North Korea sent fears soaring that the reclusive state would soon conduct its seventh nuclear test.

Before the G20, Biden will push the US's commitment to Southeast Asia in meetings with leaders from the Association of Southeast Asian Nations, seeking to counter Beijing's influence in the region.

China has been flexing its muscles — through trade, diplomacy and military clout — in recent years in a region it sees as its strategic backyard.

Biden flew into Phnom Penh with an agenda emphasising his administration's policy of "elevating” the US presence in the region as a guarantor of stability, Sullivan said.