Manouchehr Mottaki spoke in Bolivia on a tour of Latin America, where Teheran has cultivated closer ties - especially with leftist-led nations that are pushing for more distance from US policy.
"The Islamic Republic of Iran is against foreign military bases anywhere in the world," he said.
Colombian officials say the proposed 10-year lease agreement would give US forces access to at least seven military bases to boost anti-drug efforts. Bogota says the deal would not push the number of American troops and civilian military contractors beyond 1,400 - the maximum currently permitted by US law.
But the plan has nevertheless drawn opposition from a number of leaders nervous about a greater US presence in the region.
Speaking through an interpreter, Mottaki compared it to US policy toward the Middle East.
"The hegemonic policies (of the United States) in Latin America and Asia have completely failed," he said. "That's why we think all countries that want their freedom should work together to arrive at true justice in international relations."
Iran established diplomatic ties with Bolivia in late 2007 and its president, Mahmoud Ahmadinejad, visited last year. It has sold Bolivia tractors, built dairy plants and offered to help finance a state-owned cement factory.
Mottaki met Wednesday with Bolivian Foreign Minister David Choquehuanca, who told reporters there has been little movement on a cooperation accord signed in 2007. Bolivia's Senate, dominated by the opposition, has not ratified the draft agreement.
Mottaki also expressed support for a "new vision ... that is rising in Latin America," an apparent reference to a growing group of leftist presidents.