The UN's role in advancing peace and security is the focus of renewed attention at a time when the world is facing multiple challenges, Singh said in his address at the world body's General Assembly.
"The UN Security Council must be reformed and restructured to reflect current political realities. More developing countries should be included as both permanent and non-permanent members," he said.
India has been pushing for its inclusion in an expanded and restructured Security Council, a move that has been backed some key P-5 members but China has been non-committal.
"Multilateral efforts must guide our quest for peace and security, wherever they are threatened. And the centrality and contribution of the UN system to development must be restored," he said.
"Countries are now not only more interdependent, but also face new and increasingly complex challenges. For multilateralism to remain relevant and effective in the future, multilateral institutions need to be reformed," Singh said.
Singh indicated that the reforms should also encompass global financial bodies. "Multilateral Financial Institutions should also enable an enhanced voice for developing countries in their decision making structures," he said.
Singh said growing scepticism about the UN's handling of peace and security issues underlined the necessity of reforms.
He said "never has scepticism about the UN's capacity to do so been higher, or the external environment less propitious for multilateralism".
Multilateral efforts require the "building of a new international consensus, suited to our time and rooted in today?s realities. It is only such a plan of action that will enable the UN to meet the twin tests of legitimacy and efficacy," he said.