US President Donald Trump has arrived in China for a historic and high-stakes trip to meet Chinese President Xi Jinping, set to discuss economic opportunities, trade and contentious issues for the two, the Iran war and Taiwan.

As the US President touched down in Beijing, welcomed by fanfare and chants from children, Mr Trump commenced his second official visit to China while in office.

“Welcome, welcome! Warm welcome!” the young children chanted as Mr Trump disembarked Air Force One.

“Very important guest,” they continued in Chinese as Mr Trump was greeted by the vice president of China.

The move, not being welcomed by Mr Xi himself, had some wondering if it was a snub, but it was the complete opposite.

On his last trip, Mr Trump was only welcomed by a senior official and state councillor. So the upgrade to the Chinese vice president shows that China is taking this visit very seriously.

Mr Trump, who has been battling low approval numbers back home, had brought in the big guns for his visit, joined by a group of chief executives, a big flex and a potential secret weapon, including Elon Musk and Nvidia’s Jensen Huang, a late addition who boarded Air Force One during a refuelling stop in Alaska en route to the Chinese capital at Mr Trump’s request.

Many of those executives, including Mr Huang and Mr Musk, are seeking to resolve issues with China, and Mr Trump has said he will urge Mr Xi to “open up” China to US business.

But the power dynamic has shifted since Mr Trump’s last visit in 2017, when China went out of its way to lavish Mr Trump and buy billions in US goods, said Ali Wyne, senior advisor for US-China relations at International Crisis Group.

Back then “China was trying to persuade the United States of its growing status ... This time around it’s the United States, unprompted, of its own volition, that is acknowledging that status,” Ms Wyne said, pointing out Mr Trump revived the term ‘G2’, referring to a superpower duo, when he last met Mr Xi on the sidelines of an APEC meeting in South Korea in October.

This week’s meetings will provide plenty of face time between the leaders: they are scheduled to hold talks at The Great Hall of the People, tour the UNESCO heritage site Temple of Heaven and attend a state banquet on Thursday, before taking tea and lunch together on Friday, according to the White House.

But Mr Trump enters the talks with a weakened hand. US courts have hemmed in his ability to levy tariffs at will on exports from China and other nations.

The Iran war has also boosted inflation at home and escalated the risk that Mr Trump’s Republican Party will lose control of one or both legislative branches in November’s midterm elections.

Though the Chinese economy has faltered, Mr Xi does not face comparable economic or political pressure.

Nevertheless, both sides are eager to maintain a trade truce struck last October in which Mr Trump suspended triple-digit tariffs on Chinese goods, and Mr Xi backed away from choking global supplies of rare earths, vital in making items from electric cars to weapons.

They are also expected to discuss forums to support mutual trade and investment and dialogue on AI issues.

Washington looks to sell Boeing aeroplanes, farm goods and energy to China to cut a trade deficit that has long irked Mr Trump, while Beijing wants the US to ease curbs on exports of chipmaking equipment and advanced semiconductors, officials involved in the planning said.

Aside from trade matters, Mr Trump is widely expected to encourage China to convince Tehran to make a deal with Washington to end the conflict.

But analysts doubt Mr Xi will be willing to push Tehran hard or end support for its military, given Iran’s value to Beijing as a strategic counterweight to the US.

For Mr Xi, US arms sales to Taiwan, the democratically governed island claimed by China, will be a top priority, coming at a time when the People’s Republic push the message that reunification cannot be stopped.

China reiterated on Wednesday its strong opposition to the sales, with the status of a $US14 billion ($A19 billion) package awaiting Mr Trump’s approval still unclear.

The United States is bound by law to provide Taiwan with the means to defend itself, despite a lack of formal diplomatic ties.

- With Reuters