Executives from America's largest companies called Tuesday on presidents Barack Obama and Xi Jinping to focus on progress in securing a bilateral investment treaty when they meet next week.

A group of 94 CEOs have written to the two presidents to say a "high-quality" agreement would have an "immediate and tangible impact for both of our economies."

Among the signatories are Berkshire Hathaway's Warren Buffett, Apple's Tim Cook Facebook's Mark Zuckerberg and Lloyd Blankfein of Goldman Sachs.

Their call comes as the impact of weaker Chinese growth is felt across the world, from slower trade volumes to skittishness on global equity and commodity markets.

"As the two largest economies in the world, the United States and China need a positive and enduring commercial relationship, which is an essential anchor for global economic growth," the signatories said.

Obama and Xi are expected to meet next week for a summit that threatens to be overshadowed by disputes over cyber security, maritime claims and Beijing's control of its currency.

Administration officials have pointedly let it be known that Chinese firms and individuals could face sanctions for targeting US firms and stealing millions of highly sensitive government personnel files.

US Treasury Secretary Jacob Lew has also warned publicly that China would be held responsible for the political and economic impact of its currency policies after last month's yuan devaluation.

But the biggest point of contention may be in the military sphere, were China has made a series of claims to disputed territories in the South and East China Sea.

The investment treaty may provide better reciprocated market access for US and Chinese firms.

But negotiations so far have seen repeated efforts to carve out exceptions in sectors ranging from banking to aerospace, making the agreement patchy.