US President Joe Biden and his Chinese counterpart Xi Jinping on Monday held a much-anticipated first in-person meeting on the margins of the G20 summit, amid strained bilateral relations that worsened due to Beijing's recent posturing over Taiwan - including actual display of military power.

Biden and Xi shook hands and greeted each other with smiles, standing in front of a row of US and Chinese flags. This is their first face to face meeting after Biden became president two years back. They have, however, talked on phone and as vice president earlier Biden had been in touch with the Chinese strongman.

The two leaders did not wear masks.

In his opening remarks, Biden said that he was committed to keeping the lines of communication open with Xi.

"I'm committed to keep lines of communication open between you and me personally, but our governments across the board, because our two countries have so much that we have the opportunity to deal with," he said.

"As the leaders of our two nations share responsibility in my view to show that China and the US can manage our differences, prevent competition from becoming anything even near conflict and find ways to work together on urgent, global issues that require our mutual cooperation," he added.

On his part, Xi said the world is paying attention to the high-stakes meeting between him and President Biden.

"Currently the China-US relationship is in such a situation that we all care a lot about it because this is not the fundamental interest of our two countries and peoples, and it is not what the international community expects (from) us," Xi was quoted as saying by CNN.

"As leaders of the two major countries we need to chart the right course for the US China relationship. We need to find the right direction for the bilateral relationship going forward and elevate the relationship," he added, speaking through a translator.

"The world expects that China and the United States will properly handle the relationship. Our meeting has attracted the world's attention, so we need to work with all countries to bring more hope to world peace, greater confidence to global stability and strong impetus to common development," Xi said.

The Chinese leader said he was ready to have a "candid and in-depth" exchange of views with Biden on issues of strategic importance on China-US relations and on major global and regional issues.

In Washington earlier, Biden promised that he would be "straightforward" at the meeting, spell out the US red lines and learn about Beijing from Xi.

Xi arrived here on Monday afternoon, a day after Biden's Air Force One landed in Bali where leaders are gathering for the annual Group of 20 summit of the globe's major economies the advanced nations as well as the emerging economies.

Bali is the last stop in Biden's three-nation trip, which included Egypt for the environment summit COP27 and Cambodia for the ASEAN Summit. In Phnom Penh, he indicated his country's solidarity with ASEAN nations, several of whom have conflicts with an overbearing China.

He said these countries and the US can together defend against "threats to rules-based order and threats against the rule of law" a reference to China but without naming that country.

Relations between the two countries took a nosedive after US House Speaker Nancy Pelosi's visit to Taiwan in August. China saw it as a provocative US move in support of the island which governs itself, but which Beijing says must return to it someday.

After the Pelosi visit, China held a series of military exercises around Taiwan to make its concerns clear. Biden has indicated that the US would come to Taiwan's aid if China invades, a stand that has exasperated tensions.

Both leaders entered the meeting -- held at a hotel in Bali's Nusa Dua -- stronger at home.

Biden's Democratic Party has done better than expected in mid-term elections, and Xi has secured a tradition-breaking third term as the head of China's Communist Party and is being placed by many in the same league as Deng Xiaoping.

"His circumstance has changed, to state the obvious, at home," Biden was quoted as saying to reporters before his Bali arrival.

And about his own, he said, "I know I am coming in stronger."

The G20 comprises Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Republic of Korea, Mexico, Russia, Saudi Arabia, South Africa, Turkey, the UK, the USA and the European Union (EU).

Between them, they account for over 80 per cent of global GDP and 75 per cent of international trade.