The Asia-Pacific Economic Cooperation group is responsible for about half of all world trade. Its members hope to use their combined economic muscle to revive the Doha round of the World Trade Organization talks.

To do that, this week's APEC forum will urge the main trading nations to make crucial concessions on trade barriers.

The Doha negotiations on trade liberalization began in 2001 and have stalled over barriers to farm trade and imports of manufactured goods.

The United States and the European Union accuse each other of doing too little to reduce barriers on farm imports.

Many developing nations and Australia also are urging greater farm trade liberalization, while the U.S., the E.U. and other developed nations want large emerging economies, including Brazil and India, to open their markets to more industrial imports.

APEC leaders think the WTO talks have the potential to create a freer and fairer global market, particularly for the poorest nations.

Delegates also will look at ways to expand trade among APEC's 21 members.

Australian economist Stephen Harcourt says making trade flow more easily is crucial.

"It's about trade facilitation, that is standardizing customs and so on, and the World Bank says that could be worth about $440 billion so there's certainly a lot of gains to be made. Basically standards across the region, customs, basically streamlining procedures, and just making it a lot easier to get goods and services, you know, through, APEC countries [and] across borders," said Harcourt. 

There are also hopes that this week's APEC summit in Sydney will see progress in creating a Pacific-wide free trade zone, stretching from Chile to China.

Canada suggested an APEC free trade area in 2004 and the United States has become an enthusiastic supporter of the idea.

The Asia-Pacific Economic Cooperation forum began life in the late 1980s as an organization committed to trade liberalization. Business and commerce remain fundamental to APEC, although this year's conference in Australia's biggest city will also concentrate on climate change.

APEC's members include China, Japan, Russia and the United States, along with smaller economies in Asia and Latin America.