London  - Efforts to throw the world's poorest nations a lifeline took centre stage at the G20 summit in London Thursday with pledges of more than 1 trillion dollars in financial support.

The big financial pledges were hailed by US President Barack Obama as "bold action" aimed at "supporting those who do not always have a voice."

They would give the world's most disadvantaged nations a "tool to lift themselves out of poverty," he said.

The G20 moves were also seen as underscoring the importance of the role developing countries play in powering world economic growth.

"We do not want to see a decline in world trade," said Obama.

British Prime Minister Gordon Brown, who chaired the one-day meeting of the world's leading industrialized and emerging economies, described the measures as a step towards "building a fairer world."

Leading humanitarian aid organization Oxfam also praised the measures announced in London.

"This G20 summit delivers a vital pick-me-up for poor countries struggling to survive the economic crisis but much more is needed to ensure their long-term recovery," spokesman Duncan Green said.

"We welcome the 1.1 trillion dollars for global economic recovery. But we must ensure that poor countries get their fair share - that Uganda benefits as well as Ukraine."

Oxfam said it had "deep concerns" about how central the International Monetary Fund (IMF) had become in the current crisis.

"The fund has been given a blank cheque but its reform remains no more than a promise," said Green.

But War on Want, an anti-poverty campaign group, criticized the measures announced at the summit.

"The world demanded a new economic system which puts the needs of people first. Instead, the G20 have just thrown money at the failed institutions of the past," a statement said.

The measures, announced at the close of the G20 summit meeting in London Thursday, also include a 250-billion-dollar plan to shore up global trade and 100 billion dollars made available directly through the world's leading development banks.

"The G20 leaders have today sent a powerful signal that the international community is committed to support these countries, including by ensuring that the IMF has the resources available," said Dominique Strauss-Kahn, the managing director of the IMF.

"The global crisis is hitting emerging markets and poor countries hard," he added.

It was therefore imperative for global confidence and economic recovery that capital continues to flow to them.

The summit communique also pledged to reform international institutions to give poorer nations a voice.

"We will reform their mandates, scope and governance to reflect changes in the world economy and the new challenges of globalization and that emerging and developing economies, including the poorest, must have greater voice and representation," it said.

British Prime Minister Gordon Brown singled out the proposal to channel the future proceeds from agreed sales of gold held by the IMF to go to developing countries.

"The gold of the world is now being used to help the poorest of the world," said Brown. dpa