The United States accuses Iran of seeking to develop nuclear weapons and President George W. Bush has spearheaded a drive to isolate Tehran internationally. Tehran denies the charge.
Iran's Foreign Ministry spokesman also suggested Tehran would respond in an "appropriate and timely" way to any change in U.S. behaviour towards the country, which is embroiled in a row with the West over its disputed nuclear plans.
Iran, which has not had diplomatic ties with the United States in three decades, has reacted cautiously to Obama's election victory, saying it is waiting to see whether his presidency will herald real change in U.S. foreign policy.
Obama, who takes office on January 20, last week said he views Iran as a "genuine threat" but still favours initiating a dialogue with it. On Sunday, he said he will take a new approach towards Tehran that will emphasise respect for the Iranian people and spell out what the United States expects of its leaders.
"We have to see whether or not this change in orientation (by Obama) is in practice and whether it will bring about fundamental change in the behaviour and stance of America in relation to Iran," Foreign Ministry spokesman Hassan Qashqavi told a news conference.
He said Obama should not "repeat past statements and instances whose falsehood has been demonstrated by Iran," a reference to U.S. accusations about Tehran's nuclear plans and other issues — although he did not mention specific charges.
"This is a very important point and undoubtedly Iran will undertake an appropriate and timely measure proportionate with the new U.S. behaviour and action," Qashqavi said.
Obama said on Sunday he was concerned about the Islamic Republic's support of the Lebanese Shi'ite movement Hezbollah and about Iran's nuclear enrichment, which he said could trigger a Middle East arms race.
Washington also accuses Iran of backing militants in Iraq, another charge Tehran denies.
In a shift from Bush's policies, Obama has said he would seek much broader engagement with Iran, saying he was prepared to offer it economic incentives to stop its nuclear programme but also that tougher sanctions could be imposed if it refused.
Professor Mohammad Marandi, who heads North American Studies at Tehran University, said he did not believe this would make Iran stop its enrichment activities.
Iran says its programme is aimed at producing electricity so that the world's fourth largest crude producer can export more of its oil and gas.
"Iran is adamant to pursue its nuclear rights … I don't think they are going to be ready to halt enrichment," he said. "Obama has to recognise that Iran doesn't need American incentives."
(Reporting by Hossein Jaseb and Hashem Kalantari; Writing by Fredrik Dahl; Editing by Dominic Evans)
