While he did not name the US in particular, the Asia-Pacific region has seen growing economic and political rifts between China and the US result in heightened tensions.
Noting that China and Japan are close neighbours, Xi said that the two countries share many common interests and space for cooperation.
Thailand's Foreign Minister Don Pramudwinai said the meeting of the 21-member bloc "takes place at a pivotal juncture" with the world facing multiple risks.
In the leaders' declaration, G-20 nations deplored Russia's aggression in Ukraine "in the strongest terms" and demanded its unconditional withdrawal.
In August 2017, the world witnessed the beginning of history's largest and fastest exodus, with hundreds and thousands of Rohingya fleeing their homes in Myanmar.
The summit turned out to be a confirmation of each leader's differences, experts say.
He also said that the member countries have to extend the benefits of development to all human beings with compassion and solidarity.
Xi, on his second overseas trip since the pandemic, has commanded the spotlight in Bali - with officials lining up to hold face-to-face talks with the Chinese leader.
Indonesian President Joko Widodo warned that ending the war was the responsibility of nations for the sake of current and future generations.
The leaders of both nations also confirmed that Tokyo and Washington would continue to work closely on addressing issues relating to China.