Leaders gathering for the Asia-Pacific Economic Cooperation (Apec) forum in Thailand should "rise above differences", the host said on Thursday, after a series of summits in the region were dominated by geopolitical tension over the war in Ukraine.

Thailand's Foreign Minister Don Pramudwinai said the meeting of the 21-member bloc, which starts on Friday, "takes place at a pivotal juncture" with the world facing multiple risks.

"Cancel mentality... permeates every conversation and action, (and) makes any compromise appear impossible," he said in a statement after a meeting of the bloc's foreign ministers ahead of the main summit.

"That's why Apec this year must rise above these challenges and deliver hope to the world at large."

Thai Prime Minister Prayuth Chan-ocha at a pre-summit business event said the focus of meetings would be "new trade and investment narratives... the need to reconnect supply chains and travel, and the global sustainability agenda".

On the Apec sidelines, President Xi Jinping is expected to have talks with Japanese Prime Minister Fumio Kishida.

US Vice President Kamala Harris and Australian Prime Minister Anthony Albanese are among those also attending the main meeting, while French President Emmanuel Macron is a special guest.

The Apec meeting comes on the heels of the Group of 20 summit in Bali where countries unanimously adopted a declaration saying most members condemned the war in Ukraine, but that also acknowledged some countries saw the conflict differently.

Host Indonesia said the Ukraine war had been the most contentious issue.

The war also figured prominently at the East Asia Summit and the Association of Southeast Asian Nations Summits in Cambodia at the weekend, as did the crisis in Myanmar, whose ruling generals were barred from attending due to failure to follow a peace process.

Russia is a member of both G20 and Apec but President Vladimir Putin has stayed away. First Deputy Prime Minister Andrey Belousov will stand in for him at Apec. (Reuters)