Vice-Premier Wang Yang and US Treasury Secretary Jacob Lew were due to showcase Sino-US friendship on Sunday.

They were scheduled to make a boat trip at the Summer Palace in Beijing.

Lew arrived in Beijing a day before the annual China-US Strategic and Economic Dialogue, being held in the Chinese capital.

However, this friendly prelude came ahead of probable fierce arguments between the world's two largest economies over key strategic and economic issues, including the South China Sea and the Korean Peninsula, analysts said.

A 400-plus United States delegation, including more than 10 ministers, arrived in Beijing on Sunday to attend the two-day dialogue.

US Secretary of State John Kerry will co-chair the strategic part of the dialogue with State Councilor Yang Jiechi on Monday. Launched in 2009, the dialogue has become an important platform for communication between the two countries.

Ted Galen Carpenter, a senior fellow of defense and foreign policy studies at the Cato Institute, said the main issues at the dialogue are likely to be nuclear security on the Korean Peninsula, preserving and enhancing the global trading system, and the South China Sea.

"Looming in the background are specific issues such as North Korea's nuclear and ballistic missile programs, the rise of trade protectionist sentiment in the US — even as China's economy shows increasing vulnerability — and the Obama administration's policy of heightened US involvement in the South China Sea," he said.

Wang Fan, vice-president of China Foreign Affairs University, said strategic competition between China and the US is increasing even though the two countries have made progress on military and people-to-people exchanges.