US firms in Hong Kong are keeping a close eye on the upcoming meeting between Chinese President Xi Jinping and US President Donald Trump, all while looking to get involved in the "tremendous growth" of the Pearl River Delta.

The meeting between Trump and Xi is "amusing to our ears in terms of relationships developing between the US and China", said Tara Joseph, president of the American Chamber of Commerce in Hong Kong (AmCham HK), one of the largest American chambers outside the US and the largest international chamber in Hong Kong.

Joseph said it was business as usual so far. "We haven't felt any big changes in terms of business opportunities," she said.

"What we hope for is fair and free trade and anything that promotes that is important to us," she said during a recent interview in Hong Kong. "Obviously, like everybody in the world, we are concerned about changes in trade strategies and policies."

Last week, Trump signed two executive orders - one to prepare a report assessing the practices of US trading partners contributing to the US' 2016 $500 billion trade deficit and the other to improve collection of anti-dumping and countervailing duties.

Joseph said it's too early to comment on the trade policies and the chamber will be going to Washington in June to try and understand "what's happening right now".

"We'll make sure there's free and fair flow of trade around the world," she added.

US businesses' income from direct investments around the world has tripled since 2000 to 2.4 percent of GDP, with income from China making an important contribution, according to a report by Oxford Economics in January.

As the Chinese economy transitions into the modern age, there is ample reason to believe US exports can grow even more rapidly, and US firms can harvest significant revenues from their investments, said the report.

"One of the areas that is absolutely key for us as we see business going forward in Hong Kong is the One Country Two Systems principle and how that plays in commerce and business," said Joseph.

The principle presents huge opportunities for Hong Kong because the legal and financial systems in Hong Kong are familiar with international businesses and the region connects with the growing Pearl River Delta.