Iranian Foreign Minister Kamal Kharazi said in a statement that as a signatory of the Non-Proliferation Treaty (NPT) Iran had "an inalienable right" to nuclear technology for peaceful ends.
Kharazi denounced "an illegal active campaign to deprive Iran of its right ... (and) the protracted pattern of failure to facilitate Iran's access to nuclear technology for peaceful purposes."
He also criticised what he called a return to a militaristic and unilateral approach to international relations since the September 11, 2001 terror attacks on the United States, an implicit reference to US policy.
In the message, read out to delegates, he also said that reductions, either unilateral or bilateral, in nuclear arsenals announced by the main nuclear powers like the United States and Russia were "unverifiable and limited."
In addition, nothing guaranteed that they could not be reversed, the minister added.
For his part the president of the conference, Kenyan Amina Mohamed, welcomed the recent decision by Iran to sign the additional NPT protocol, which allows greater scope for verification, and to suspend all uranium enrichment and reprocessing.
Under international pressure, notably from the United States, the Iranian government agreed last November to suspend its uranium enrichment programme to prove to the IAEA (the International Atomic Energy Agency) that it was not secretly trying to develop nuclear weapons, as Washington had suggested.
Last Thursday, speaking at the International Economic Forum in the Swiss resort of Davos IAEA director Mohamed ElBaradei said refusal by Iran to cooperate fully with the UN nuclear regulating body would have had "serious implications".
Iranian President President Mohammad Khatami, who also attended the Davos meeting, said there that Iran had never possessed atomic weapons and had no intention of acquiring them.