The United States and Australia unveiled a six-nation "Beyond Kyoto" pact today to combat global warming.
The two countries said the Asia-Pacific Partnership on Clean Development and Climate to promote new technologies to cut greenhouse gases was not a threat to the existing Kyoto Protocol.
But critics said it offered no targets and would undermine existing treaties.
]"We are not detracting from Kyoto in any way at all. We are complementing it," US Deputy Secretary of State Robert Zoellick told a news conference on the sidelines of an Asia-Pacific security forum in the Lao capital, Vientiane.
"Our goal is to complement other treaties with practical solutions to problems," he said alongside ministers from Australia, China, India, Japan and South Korea.
The six nations, which account for nearly half the world's population and greenhouse emissions, said the pact would "seek to address energy, climate change and air pollution issues within a paradigm of economic development".
The non-binding deal includes no Kyoto-style limits on emissions and no timeframes.
The United States and Australia are the only developed nations outside Kyoto, which demands cuts in greenhouse emissions to 5.2 per cent below 1990 levels by 2008-12. Both say Kyoto is flawed because it omits developing states.
China and India have ratified Kyoto, but being developing countries they are not required to meet its obligations.
China, which fears environmental restrictions could hamper its fast-growing economy, called the new pact a "win-win solution" for developing and developed nations.
But environmentalists criticised it as a US attempt to create a distraction ahead of UN talks in November in Montreal, which will focus on how to widen Kyoto to include developing nations after 2012.