The United States and Australia, the only two countries that have refused to ratify the Kyoto Protocol, pledged on Wednesday to work within the UN system on a post-Kyoto treaty on climate change.
But their efforts to influence the direction of the debate have aroused suspicion among developing countries including China ahead of a summit of Asia-Pacific leaders here, diplomats said.
President George W Bush and Prime Minister John Howard said in a statement they "look forward to working actively and constructively with all countries at the UN Climate Change Conference in Indonesia in December".
The Kyoto Protocol expires in 2012, and Washington and Canberra will press for a new agreement that provides for "effective action from all the major emitting nations" on the greenhouse gases blamed for global warming.
Both the United States and Australia rejected the Kyoto accord on the grounds that it did not commit developing countries to the same sort of emissions cuts required from industrialised nations.
Bush, who is on a state visit to Australia, stressed at a joint news conference with Howard that rising Asian giants China and India in particular needed to be party to the new deal if it is to have any real effect.
"If you really want to solve the global climate change issue, let's get everybody to the table, let's make sure that countries such as China and India are at the table as we discuss the way forward," he said.
Bush said he would raise the issue with Chinese President Hu Jintao at a meeting on the sidelines of the APEC summit.
Howard has put climate change high on the summit's agenda, proposing a "new template" after 2012 that would call on developing nations to do more to cut their own emissions.
This has met with robust opposition from developing states, who accuse Australia of undermining the Kyoto accord and the UN Framework Convention on Climate Change (UNFCC).
An Indonesian diplomat said Australia should allow the UNFCC to take the lead in planning strategies for the post-Kyoto world. The UNFCC is holding its next meeting on the Indonesian resort island of Bali in December.
"We don't want any duplication of the UN framework. There should be no action plans in the statement" at the APEC summit, the diplomat said.
A senior Asian foreign ministry official said he and his colleagues from the Association of Southeast Asian Nations (ASEAN) met on Monday to coordinate their positions on the climate change statement.
"China supports the ASEAN bloc," he said.
China, one of the world's biggest emitters of greenhouse gases, has said it should not be expected to take drastic action because it needs to focus on lifting its people out of poverty through economic growth.
APEC is not expected to produce a firm target for a reduction in greenhouse gas emissions, with a leaked draft declaration referring only to an "aspirational goal."
The joint statement by Bush and Howard on Wednesday was also couched in general terms, calling for consensus on a "long-term global goal for reducing emissions."
The two countries stressed the role of new technologies in reducing emissions, noting "the important contribution nuclear power can make in meeting energy needs and addressing the challenge of climate change."
Bush has called a meeting of 16 nations, which together account for 80 per cent of greenhouse gas emissions, to discuss climate change in Washington on September 27-28 ahead of the Bali meeting.
This move has been met with suspicion by environmental activists, notably in Europe, who believe the United States wants to subvert the mandatory Kyoto approach with voluntary measures based on new technologies.