World leaders including Barack Obama and Vladimir Putin have converged on Beijing for an Asia-Pacific summit against the backdrop of a US-Russian chill and the relentless rise of the meeting's increasingly assertive host.

The gathering which started on Monday is the biggest event yet hosted by Chinese President Xi Jinping, who took over last year.

The annual two-day summit of Asia-Pacific Economic Cooperation (APEC) countries is a rare chance for such a wide range of top leaders to be in the same room, and the pledges of amity and trade convergence are typically balanced by tense sideline exchanges on festering geo-political problems.

The presence of Obama and Putin promises to be awkward, with Russia under Western pressure and economic sanctions over its seizure of the Crimea this year and its role in a separatist war in eastern Ukraine.

Obama and Putin are not expected to hold talks, but Australian Prime Minister Tony Abbott has vowed to confront the Russian leader over Malaysia Airlines flight MH17, which was brought down over eastern Ukraine in July, with 38 Australians among the 298 dead.

The West has accused pro-Russian rebels of blasting it out of the sky with a missile and Moscow of impeding an investigation. Russia denies the accusations.

China and the United States also have jousted over differing visions of how to achieve Asia-Pacific trade integration, adding to persistent discord over commerce, human rights, US accusations of Chinese cyber-espionage, and the territorial disputes.

Beijing's growing territorial assertiveness in the South China Sea also has rankled rival claimants to parts of the strategic waterway.

It will be all smiles, however, when the APEC leaders gather on Monday for the annual "family photo," typically wearing the host's national dress. This year's fashion choice remains a mystery.

The event culminates on Tuesday with a formal leaders' summit.