Melbourne, Dec. 12: Developed countries have been warned that they must do "significantly more" in cutting their greenhouse gas emissions.

At the start of the leaders session of the United Nation's conference on climate change in Bali, Indonesian President Susilo Bambang Yudhoyono said that all countries needed to do things differently, and do something more.

But he said the principle of "common but differentiated" responsibilities and the international community had accepted capabilities since the Rio Earth Summit in 1992 and this should be part of the solution.

"Unfortunately, for so many years we have not given the concept enough flesh and bone, " The Australian quoted him, as saying.

In a pointed message to the developed countries, Yudhoyono said they needed to do "significantly more" to cut their own level of emissions.

He said it was essential for the United States to be part of any post 2012 arrangement because "otherwise we will not be able to effectively address the climate change issue".

For developing countries, a commitment to sustainable development was needed, he added.

Australian Prime Minister Kevin Rudd was greeted with warm and extended applause for his decision to ratify the Kyoto Protocol.

Yudhoyono singled out Rudd for praise for his "speedy ratification".

"I say to you Mr. Prime Minister: Welcome aboard, " he said.

United Nation's secretary general Ban Ki-moon said reaching a comprehensive agreement would not be easy, but parties needed to use the Bali talks to promise that they would reach a comprehensive deal by the effective deadline of 2009.

Moon said the challenge facing the nations was an ethical one, and those countries with the least resources to deal with climate change needed the most help.

Ending the conference without a consensus should be avoided at all costs, Yudhoyono said, because this was not the time to let momentum slip. (ANI)