"In no way do the results of the conference measure up to the actions needed to address the scale and depth of the economic meltdown, most evident in the jobs crisis, particularly in developing countries," a statement by the body said.
The umbrella organisation said that the document was merely a non-binding appeal for fiscal stimulus measures, debt cancellation, grants to poor countries, and for donor countries to honour their aid pledges.
'Lack of detail'
Gemma Adaba of the International Trade Union Confederation said the declaration contained few measures to ensure that rich countries fulfil commitments to boost aid to the developing world.
The document also failed to maintain pressure on the International Monetary Fund (IMF) and World Bank to make changes for the good of poor countries, she said.
Diplomats from the Group of 77 bloc of developing nations said that the final document achieved less than hoped for.
However, they said that the declaration had succeeded in covering the main issues of contention.
"You have to compromise at the UN … Otherwise you will end up with nothing," one senior G77 diplomat said.
While 140 countries attended the UN conference, several Western countries did not send representatives, meaning that the meeting was overwhelmingly attended by developing nations.
The United States and European Union were expected to tell their delegations at the General Assembly to distance themselves from some of the language in the final declaration, diplomats said.
The final document was watered down from an earlier version prepared by Manuel D'Escoto, the president of the General Assembly, after Western nations raised objections to the scope of the draft.
Less than a dozen presidents and prime ministers, mostly from Latin America and the Caribbean region, attended the conference. Others countries sent lower-level delegates.