Yoshihiko Noda also said that a pledge by Japan's Finance Minister Jun Azumi on January 12 to join Washington's campaign represented only the finance minister's "personal view."
Azumi had said Japan wanted to "take planned and concrete steps to further reduce" Tokyo's dependence on Iranian crude oil.
Azumi's comments also seem to be at odds with a statement made by Japan's foreign minister, who said that Tokyo is "extremely circumspect" about the U.S.-led drive to impose sanctions on Iranian oil exports.
Koichiro Gemba told a press conference in Tokyo on January 13 that "the United States would like to impose sanctions. We believe it is necessary to be extremely circumspect about this matter."
Gemba added that Japan will carefully assess the issue before making a decision.
Meanwhile, Russian Deputy Foreign Minister Gannady Gatilov warned that new sanctions against Iran will be seen as a bid to change Iran's leadership.
Gatilov's comments came as EU governments are inching closer to an agreement on an Iranian oil embargo that would give firms up to six months to phase out business with Tehran.
compiled from agency reports