Washington: US President George W. Bush hopes to push momentum for a world trade pact and a global target on climate change at this week's Asia-Pacific summit but the Iraq debate at home looms as a distraction.

Bush will meet in Sydney with the leaders of Australia, China, Japan, Russia and other members of the Asia-Pacific Economic Cooperation forum. He leaves Washington on Monday and is due to arrive in Australia on Tuesday evening.

The trip marks Bush's seventh to APEC, and he has vowed to keep an active presence in the Asia-Pacific region amid nervousness among some US allies over China's rising clout.

But Bush has drawn criticism for his plans to leave the summit a day before its official end. He will rush back home to prepare for a crucial progress report on Iraq from US commander Gen. David Petraeus and Ambassador Ryan Crocker.

The Petraeus-Crocker report is a focal point of an intensifying debate over whether United States should withdraw its forces from Iraq. The issue threatens to intrude on Bush's agenda at APEC, a forum of 21 economies that account for 60 per cent of global gross domestic product.

In Sydney, Bush's highest priority will be breathing life into the moribund Doha round of world trade talks, which suffered a major setback at a June meeting in Germany.

Bush will press his counterparts to reinvigorate efforts toward a global trade pact billed by supporters as a way of boosting world growth and lifting millions out of poverty.

Bush also wants to begin drawing China and India further into the fold of discussions on a global pact to reduce greenhouse gas emissions that cause global warming.

"I don't want to single out China, but China has got a major role to play," Bush said in a round-table interview with Asia-Pacific newspapers. "Any agreement without China is not going to be an effective agreement."

After long resisting numerical targets on emissions cuts and rejecting the U.N.-sponsored Kyoto treaty, Bush in May called for a long-term global goal to cut emissions and urged a series of meetings among major polluting countries. Washington will host the first of those sessions on Sept. 27-28.

Australian Prime Minister John Howard wants APEC leaders to agree to the idea of an "aspirational" goal on emissions cuts.