UN Secretary-General Antonio Guterres on Tuesday urged the United States and China to engage in dialogue, warning of an increasingly divided world.

"I fear our world is creeping towards two different sets of economic, trade, financial and technology rules, two divergent approaches in the development of artificial intelligence -- and ultimately two different military and geopolitical strategies," Guterres said as he opened the annual UN General Assembly.

"This is a recipe for trouble. It would be far less predictable than the Cold War. To restore trust and inspire hope, we need cooperation," he said.

"We need dialogue. We need understanding."

The summit will feature the first speech to the world body by US President Joe Biden, who has described a rising and authoritarian China as the paramount challenge of the 21st century. 

Chinese President Xi Jinping is also set to address the United Nations but by video in light of Covid restrictions.

Guterres said that divisions between the two powers set back efforts on other key priorities including reversing coups. 

Since February, militaries have seized control both in Myanmar and Guinea and Afghanistan's Western-backed government collapsed to the Taliban.

"We are also seeing an explosion in seizures of power by force. Military coups are back. The lack of unity among the international community does not help," Guterres said.

"Geopolitical divisions are undermining international cooperation and limiting the capacity of the Security Council to take the necessary decisions."