Southeast Asian leaders called Friday for a legally binding global pact on climate change and urged richer nations to provide them with "scaled-up" financial help to combat its effects.

In a joint summit statement, leaders of the Association of Southeast Asian Nations (ASEAN) meeting in Vietnam said a new deal should go further than the non-binding 11th-hour pact reached in Copenhagen in December.

All parties under the UN Framework Convention on Climate Change should "work together to secure a legally binding agreement, particularly to limit the increase in average global temperature to below two degrees Celsius above the pre-industrial level," the statement said.

The Copenhagen Accord calls for limiting global warming to two degrees Celsius (3.6 degrees Fahrenheit), the threshold set by many scientists.

But critics have complained that the actions are only voluntary and lacking in vital details on how to achieve the goal.

Environmental campaigners at Greenpeace dismissed the ASEAN leaders' statement as "weak and compromising" in not criticising the Copenhagen pact in stronger terms.

A drought currently affecting the region could have encouraged leaders to say more, said the group's Southeast Asia adviser, Zelda Soriano.

"(The drought) should have moved ASEAN leaders to make a bolder, stronger statement that places the interests and welfare of their citizens before everything else," said Soriano in a statement.

The Copenhagen deal commits rich countries to paying out around 30 billion dollars in total over the next three years and sets a potential figure of 100 billion dollars annually by 2020 for climate change action.

ASEAN leaders also "urge developed countries to... provide scaled-up, new and additional, adequate and predictable funding to the developing countries," their statement said.

The leaders urged richer countries to "continue taking the lead" with improved targets for cutting carbon dioxide emissions blamed for climate change, but said they should take care not to affect trade.

In the statement, the ASEAN leaders say they will also consider "the possibility of developing an ASEAN action plan to better understand and respond to climate change".