"Toward the end of summer we will hopefully be there for the (UN) General Assembly and I will be ready for one-on-one talks with Mr Obama, in front of the media of course," Mr Ahmadinejad said in an address broadcast live on state television.
"We are ready to sit down with Mr Obama face-to-face and put the global issues on the table, man-to-man, freely, and in front of the media and see whose solutions are better."
Iran’s hardline president suggested such a debate last September, but his offer was not taken up by Washington. He has said Mr Obama’s predecessor, George W. Bush, had declined similar invitations because he was “scared”.
Mr Ahmadinejad has on various occasions blamed the United States for “global disorders”, particularly the global financial crisis.
His call on Monday comes after a series of punitive sanctions imposed on Iran by the UN Security Council, the United States and the European Union over Tehran’s controversial nuclear programme.
Mr Ahmadinejad criticised Mr Obama for missing what he said were “historic opportunities” to repair relations with Iran, with whom the United States has had no direct diplomatic ties for more than 30 years.
Mr Obama had in March 2009 extended a hand of diplomacy towards Iran in an attempt to break the deadlock between the two countries, but since then, the animosity between the two nations has steadily worsened.
Mr Ahmadinejad said: “Somebody should answer questions whether the US government is dominated by the Zionists or the Zionist regime is controlled by the US government.”
Israel, like the United States, has not ruled out a military strike against Iran to halt its nuclear programme.
Mr Ahmadinejad, under whose presidency Iran has been slapped with four sets of UN sanctions, has remained steadfast in pursuing a sensitive uranium enrichment programme, which Washington and other world powers want Tehran to abandon.
Iran says it is not enriching uranium for any military aims.