Pacific Rim nations called for a new way forward on free trade amid the virtual collapse of global talks as they focused on keeping open fast-changing areas such as food and clean energy.

Senior trade officials from Apec - the 21-member body that accounts for more than half the world economy - voiced frustration at the standstill in the so-called Doha round that has tried for a decade to forge a global trade pact.

"All ministers agreed that we cannot simply keep doing what we have been doing in the Doha talks if we mean to move forward," US Trade Representative Ron Kirk said after the talks in Big Sky, Montana.

A senior Chinese official blamed unspecified countries' domestic politics and "shortcomings of the multilateral system" for the dire state of the Doha talks.

But Assistant Commerce Minister Yu Jianhua said China was committed to liberalisation both at home and abroad, acknowledging that the world's second largest economy was increasingly dependent on foreign trade.

Yu said the Doha round should fulfil the mission stated when the talks began in the Qatari capital in 2001 of trying to benefit the poorest countries that felt left out of previous rounds of liberalisation.

The fate of WTO talks will also be on the table next week in Paris at the 50th anniversary of the Organisation for Economic Co-operation and Development, which groups 34 advanced or well-developed economies.

Australian Trade Minister Tim Gloser, who will lead a key session in Paris, warned that a complete collapse of trade negotiations would set off a damaging wave of protectionism around the world.

Separately, Apec officials called for an "open and transparent" trade of food amid concern that unstable prices would lead to export controls.

They asked the 21 economies to "reduce unnecessary requirements in official export certificates for agricultural products" and to "eliminate requirements that are not based on science."