"We think our talks ... can go forward with one word," Saeed Jalili told students and reporters at Kazakhstan's Almaty University of Power Engineering and Telecommunications ahead of the talks with the five permanent U.N. Security Council members -- the United States, Britain, France, Russia and China -- and Germany.
The word is "right," he said.
"That is the acceptance of the rights of Iran, particularly the right to enrichment," Jalili said.
"By using a single word, [the talks] can find their way forward," he said.
The Security Council has passed a half-dozen resolutions since 2006 saying Iran relinquished its right by hiding its enrichment program from U.N. inspectors in violation of the Nuclear Non-Proliferation Treaty, which Tehran signed.
P5-plus-1 officials have said any formal acknowledgment of Iran's right, granted by the treaty for a peaceful nuclear program, would come only after Tehran restores confidence in its nuclear plans.
The talks in Almaty, Kazakhstan's largest city and former capital, were to start at 10:30 a.m. (12.30 a.m. EDT) and run through Saturday afternoon.
After Jalili's speech, an Iranian diplomat told The Wall Street Journal Tehran was open to most demands made by the P5-plus-1 in February, but first required the group's public acceptance of Iran's enrichment rights.
February's demands offered sanctions relief if Tehran agreed to suspend its 20 percent enrichment, remove most of its stockpile of already produced 20 percent enriched uranium and stop activities at its deep-underground Fordo uranium-enrichment plant south of Tehran, near the holy city of Qom.
The February demands were a concession. The P5-plus-1 previously called for Fordo, in a fortified bunker seen as largely immune to U.S. or Israeli military strikes, to be closed and for all higher-enriched uranium to be taken out of Iran.
If Iran complied with the demands, it could see an end to trade barriers on its petrochemical sector and permission to resume trading in gold and other precious metals, which would ease the tight financial restrictions Washington and the European Union placed on the country, P5-plus-1 diplomats said.
The P5-plus-1 would also halt pushes for fresh sanctions over Iran's program, the diplomats said.
Jalili said in February he considered the proposal "positive."
Iran insists its nuclear program is simply developing civilian nuclear power.
Western diplomats said Thursday they did not expect a major breakthrough in Almaty, with Iranian elections coming up in June to replace outgoing President Mahmoud Ahmadinejad.
The Kazakhstan talks are expected to be the last round of diplomacy until after the elections, U.S. officials said.
President Barack Obama said last month Iran was "over a year or so" from being able to develop nuclear weapons.