Lula told dozens of world leaders gathered for the Assembly's annual high-level debate, held at the UN headquarters in New York, that they were meeting at a time when long-predicted economic crises have become "today's harsh reality."
His remarks echoed the comments of Secretary-General Ban Ki-moon, who earlier urged world leaders to rise to the "challenge of global leadership" to defeat the most pressing problems, including the current financial crisis.
"Only decisive action by governments, especially in countries at the heart of the crisis, will be able to control the disorder that has spread through the world's financial sector, with perverse impacts on the daily lives of millions of people," Lula said.
He warned that "a crisis of such magnitude will not be overcome with palliative measures. Mechanisms for both prevention and control are needed to provide total transparency to international finance.
"International economic institutions today have neither the authority nor the workable instruments they need to inhibit the anarchy of speculation. We must rebuild them on entirely new foundations."
The Brazilian President cautioned that the crisis was too serious "to be left in the hands of speculators," adding that all too often their profits were privatized while their losses were socialized.
"The global nature of this crisis means that the solutions we adopt must also be global, and decided upon within legitimate, trusted multilateral fora, with no impositions. The United Nations, as the world's largest multilateral arena, must issue a call for a vigorous response to the weighty threats we all face."
He stressed that the world was facing many other "equally serious matters," including the food crisis, the spike in energy prices, the deadlock on talks to reform international trade, and the continuing degradation of the environment.
The President said Brazil's own experience illustrated that sugar cane ethanol and biodiesel production can reduce global dependency on fossil fuels and at the same time create jobs, regenerate degraded land and expand food production.
"Attempts to tie high food prices to the dissemination of biofuels do not stand up to an objective analysis of reality," he added, calling for a multilateral approach to solve the food and energy crises.