The United States broke off diplomatic relations with Iran in 1980, the year after the Iranian Revolution, when the Washington-backed shah was deposed, and during the 444-day embassy hostage crisis.
"We believe that restoring relations between the American and Iranian nations would be a positive move," Mottaki was quoted by the official IRNA news agency as saying at Iran's UN mission in New York.
Late last month, the George W. Bush administration was reported to be toying with the idea of opening "a U.S. interests section" in Iran similar to the mission Washington runs in Cuba despite an almost 50-year embargo against the country.
An interests section is similar to an embassy, but without an ambassador. It allows for a U.S. presence in a country with which the United States has no diplomatic relations.
White House and State Department officials said the potential mission in Iran would be aimed at reaching out to the Iranian people rather than the Iranian government.
IRNA said last week that Tehran is ready to consider an official request from Washington for such an office. Washington has not made any formal request on the issue.
However, Mottaki linked a U.S. presence in the Islamic Republic to Tehran's two-year-old proposal to launch direct flights between the two countries.
"Last year, we proposed that the Americans launch direct flights between Iran and the U.S. The two countries could study direct air services and a U.S. interests section in Tehran," Mottaki said.
Iran is embroiled in a standoff with the West over its controversial nuclear program. The regime is suspected of secretly building nuclear weapons, but Iran says it needs nuclear technology only to produce electricity.
Washington, which insists Iran's uranium enrichment program is a threat, has refused to rule out the use of force if Iran refuses to drop its nuclear ambitions.
