"Iran is not afraid of threats regarding the possible referral of its nuclear dossier to the UN Security Council," said foreign ministry spokesman Hamid Reza Asefi.
"We are not worried about such threats, although we are trying to sort out the problem through the IAEA and its board of governors," he told a press conference, referring to the International Atomic Energy Agency.
The United States and Israel, which both accuse Iran of seeking to make an atomic bomb, want the case sent to the Security Council -- which could impose sanctions on the Islamic republic.
But IAEA director Mohamed ElBaradei said during a visit last week to Israel -- widely believed to be the only nuclear power in the Middle East -- that such a referral would only complicate matters.
"Considering Iran's transparency and cooperation, there would be no reason to send our dossier to the Security Council," Asefi said.
Asefi also confirmed that Iran, which says its nuclear ambitions are limited to producing electricity, had taken the "political decision" to resume the manufacture and assembly of centrifuges but said that unspecified technical issues had yet to be resolved.
Last month, Iran announced it would go back on its commitment to Europe's so-called "Big Three" -- Britain, France and Germany -- to suspend production of centrifuges, which can be used to make bomb-grade uranium.
The move followed an IAEA resolution deploring Iran for its "lack of cooperation" with the international community over its nuclear actvities.
Asefi, however, said the manufacture of the centrifuges, which can also be used for peaceful purposes, will take place under IAEA control.
Iranian leaders have also said they do not intend to start the process of enriching uranium to make it useable in weapons.