"We have clearly defined our position on the issue of the moratorium and enrichment activities," Ali Larijani told reporters.
The Iranian top nuclear negotiator added that the Western countries will need "new initiatives to consider."
He said a solution to the Iranian nuclear program could be found through the good will of the negotiating parties.
The five permanent members of the UN Security Council, plus Germany, have demanded that Tehran suspend all uranium enrichment before negotiating a solution to the dispute.
Iran has defied three consecutive UN resolutions against its nuclear program since last year, insisting its nuclear program, which includes a Russian-built nuclear power plant in the south of the country, is for purely peaceful purposes.
Iranian President Mahmoud Ahmadinejad announced in early April the start of uranium enrichment on an industrial scale.
Iran's top nuclear negotiator said earlier this week that the country would not stop its enrichment program even if new UN sanctions are introduced.
However, Iran has recently increased cooperation with the International Atomic Energy Agency (IAEA), and invited weapons inspectors to visit a 40-MW heavy water reactor in Arak in July.
The pact, signed between the IAEA and Iran in August, allowed Tehran to solve each of the disputes surrounding its nuclear plan in turn, but was criticized by many Western diplomats.
Iran has repeatedly stated that a halt of enrichment activities is absolutely unacceptable, since it has an unalienable right to a peaceful nuclear program under the Nuclear Non-Proliferation Treaty (NPT).
The United States, Britain and France have once again urged the UN to exert pressure on Iran and work out a new resolution imposing fresh sanctions on Iran.
