In a speech to the UN world summit, he also said the US had failed its own people in its response to Hurricane Katrina, accused Washington of fuelling terrorism and faulted it for its doctrine of pre-emptive military strikes.
"Today we know there were never weapons of mass destruction in Iraq but despite that, and going over the head of the UN, Iraq was bombed and occupied. So the UN must be pulled out of the US," Chavez said.
The three-day New York summit was convened to mark the UN's 60th birthday by laying out a plan for multilateral action in the new century on terrorism, human rights, development, peacebuilding and UN management reform.
Calling for change
Chavez branded the plan "illegal" for failing to respect anti-poverty goals set by a UN summit in 2000 and said the UN instead needed drastic overhaul.
"The United Nations has outlived its model. It's not just a question of bringing about reform. The 21st century requires profound changes," he said.
"Today we know there were never weapons of mass destruction in Iraq but despite that, and going over the head of the United Nations, Iraq was bombed and occupied"
Among changes he advocated were expansion of the 15-nation UN Security Council, which has global authority over matters of international peace and security; strengthening the role of the secretary-general, and eliminating the council veto granted the United States, China, Russia, Britain and France.
Chavez noted bitterly that US television evangelist Pat Robertson, a strong supporter of President George Bush who called for Washington to assassinate him, remained a free man.
"This is an international crime, terrorism," Chavez said.
Ties between the US and Venezuela, the world's fifth largest oil exporter, have been frosty since Chavez came to power in 1998, ushering in social reforms and forging close ties with communist Cuba.