Switzerland says United Nations Secretary-General Kofi Annan was right to criticise member states for failing to make significant progress in a number of key areas.
Speaking on Wednesday at the opening of a three-day summit of 150 world leaders, Annan said nations had come up short on efforts to tackle poverty and reform the world body.
Annan was also highly critical of the failure to reach an agreement on how to tackle nuclear non-proliferation and disarmament.
"We welcome the realistic analysis by the secretary-general," Swiss President Samuel Schmid told swissinfo. "We agree with his assessment that member states have made progress on some crucial points which have to be worked on in the coming weeks and months.
"But we also welcome that he did not hide his disappointment over the fact that nations have not been able to find solutions in other areas like, for instance, disarmament."
In a passionate address on Wednesday, Annan touched on a number of contentious issues that have dogged the summit.
Late on Tuesday the 191 UN member states finally reached agreement on a document that world leaders are expected to adopt on Friday.
But the 35-page document, which is the result of weeks of tough negotiation, is not the blueprint Annan had hoped for to tackle poverty and overhaul the world body.
The UN secretary-general gave a frank assessment of the lack of progress on reforming the world body as it celebrates its 60th anniversary.
"Let us be frank with each other and the peoples of the United Nations. We have not yet achieved the sweeping and fundamental reform that I and many others believe is required," he said.
The document consists of a watered-down declaration on development, human rights, terrorism and global security.
But negotiators failed to agree on how to tackle nuclear non-proliferation or on a definition of terrorism. They also fell short on commitments to more aid and to remove trade barriers – a major priority for developing nations.
Speaking on Wednesday, Annan again rounded on world leaders to take immediate steps to reduce poverty and bring hope to billons around the world.
"What the world needs now is leadership that will see this summit's development decisions implemented fully and without delay," he said.
"We have an opportunity to save tens of millions of lives over the next decade, and to lift hundreds of millions of people out of poverty. We must not disappoint them."
His concerns were echoed by a number of other speakers who urged the forthcoming 60th General Assembly to make the Millennium Development Goals (MDGs) a priority.
The MDGs include targets to cut extreme poverty and child mortality by half and to reverse the spread of HIV/Aids by 2015.
Paul Wolfowitz, head of the World Bank, called on nations to make good on their "bold promise" of 2000.
"Five years ago, a remarkable vision was laid out in this very hall," said Wolfowitz. "A vision which spelled progress and hope for humanity. It is time to deliver."
Despite unbridgeable splits among members countries on a number of issues, the UN Security Council unanimously passed two resolutions on the first day of the summit – one to prevent the incitement of terrorism and the other to prevent conflict, especially in Africa.
President Bush, who was quick to embrace the resolution on terrorism, said the world had "a solemn obligation to stop terrorism in its early stages".
Schmid, who leads Switzerland's delegation in New York, joined other heads of state in signing an international convention for the suppression of acts of nuclear terrorism.
The Swiss president, who is due to speak to the UN on Thursday, held bilateral talks on Wednesday with counterparts from Burundi, Mozambique and Portugal.
He joined a round-table working group on UN reform and is due to meet Italian premier Silvio Berlusconi on Thursday.
swissinfo, Adam Beaumont in New York
150 heads of government and state are taking part in the UN's biggest summit.
The meeting is taking place in New York over three days to discuss reforms of the organisation and to celebrate its 60th anniversary.
Shortly before the summit, the UN member states agreed on a final declaration to be issued at the end of the meeting.
This declaration confirms the main points of the UN Millennium Development Goals.
The UN Security Council unanimously passed two resolutions on the first day of the summit: one to prevent the incitement of terrorism and the other to prevent conflict, especially in Africa.
World leaders said there should be no let-up in the fight to reduce poverty but they were criticised by UN Secretary-General Kofi Annan for not moving fast enough on reform of the world body.