"We will not discuss the legitimate rights of Iran," foreign ministry spokesman Mohammad Ali Hosseini told a news conference.

UN Security Council powers, which fear Iran is seeking to develop a nuclear weapon, have slapped two sets of UN sanctions against Tehran over its refusal to suspend uranium enrichment.

"We can negotiate about the concerns of the different parties and the non-diversion of the Iranian nuclear programme," said Hosseini, referring to Iran's insistence that its atomic drive is peaceful.

"We are doing nothing that is against the nuclear Non-Proliferation Treaty and so there is no reason or logic for a suspension," he said.

Ahmadinejad is on Monday due to visit the uranium enrichment facility in Natanz -- Iran's most sensitive nuclear site -- to mark the Islamic republic's day of nuclear technology.

He is expected to use the occasion to make a major announcement on Iran's nuclear programme after repeatedly promising "good news" in the near future.

Iran has said it wants to install 3,000 uranium enriching centrifuges at an underground facility at Natanz and observers are expecting the announcement to refer to progress in Iran's enrichment.

Uranium enrichment is highly sensitive as the process can be used both to make nuclear energy and the explosive core of a nuclear bomb. Iran insists it has every right to the full nuclear fuel cycle.