The U.N. nuclear agency wants to hold rare talks about the volatile Middle East and efforts to rid the world of atomic bombs.
The International Atomic Energy (IAEA) has invited all of its members including Israel, the Arab states and Iran to attend the proposed forum in November.
Israel and some Arab nations indicated readiness to take part, but Iran said it saw no justification for such a meeting now.
Iran's envoy to the IAEA responded to the invitation from agency head Yukiya Amano by criticising Tehran's enemy Israel, which is widely believed to have the Middle East's only nuclear arsenal.
"We are of the view that stability cannot be achieved in a region where massive imbalances in military capabilities are maintained particularly through the possession of nuclear weapons which allow one party to threaten its neighbours and the region," Iranian ambassador Ali Asghar Soltanieh said.
Nuclear weapons are especially controversial in the Middle East, with Arab states often criticising Israel over its presumed nuclear arsenal.
Israel and the United States see Iran as the region's main proliferation threat, accusing Tehran of covertly seeking to develop nuclear arms, however Iran denies this.
A gathering of regional adversaries around the same table to talk about nuclear arms could be symbolically important, even though substantive progress is likely to remain elusive.
Amano, the IAEA's director general, said in the report that he had written to all IAEA member states about taking part in a November forum in Vienna.
Debate would focus on lessons learnt and relevant experience for the Middle East from the establishment of nuclear weapons-free zones in other regions, such as Africa and Latin America.
Diplomats stress that no decisions are expected at the planned talks, but that they can be useful as a way to start a dialogue and help build badly needed confidence in the region.
Amano said in his September report, the Application of IAEA Safeguards in the Middle East, that he had sought the views of Middle East countries on the agenda for the planned forum.
Twelve Middle Eastern states, including Egypt, Iran, Israel, Saudi Arabia and Syria, had written back, Amano added.
He suggested that his efforts had been broadly welcomed, even though some Arab states sought changes to the agenda.
He then "wrote to all member states inviting them to take part in the Forum to be held on November 21-22, 2011 at IAEA headquarters in Vienna," the report said.
Amano "will pursue further consultations with member states of the Middle East region and with other interested parties on arrangements conducive to the Forum being a constructive contribution towards the objective of the establishment" of a nuclear weapons-free zone in the Middle East, it added.
Amano said he saw "momentum" for his plan to host discussions between Israel and Arab states.
IAEA members decided in 2000 that such a meeting should take place but agreement on the agenda and other issues has been lacking.
"A nuclear weapons-free zone in the Middle East will not be achieved tomorrow, everyone knows it, but we can get closer," Amano said last month. "Increasing confidence is very much needed, even a small step is helpful."
Israel is widely assumed to hold the Middle East's only nuclear arsenal and is also the only country in the region outside the nuclear Non-Proliferation Treaty (NPT).
Arab states, backed by Iran, say this poses a threat to peace and stability. They want Israel to subject all its atomic facilities to IAEA monitoring.
Israel, which has never confirmed or denied having atom bombs, says it will only join the NPT if there is a comprehensive Middle East peace. If it signed the pact, the Jewish state would have to renounce nuclear weaponry.