"The issue of our country's peaceful nuclear activities will be on the agenda of talks between Iran and the P5+1 (the five permanent UN Security Council members plus Germany)," foreign ministry spokesman Ramin Mehmanparast told reporters in a televised briefing.
"Our main demand is recognition of our right to possess the (nuclear) technology for peaceful purposes," Mehmanparast said.
"That right has been achieved, and we don't think there is a negotiable issue regarding our nuclear activities."
Tensions have risen dramatically this year over Iran's nuclear programme, which much of the West suspects includes research to develop atomic weapons.
Mehmanparast's comments came on the second day of a two-day visit by officials from the UN nuclear watchdog for talks focused on "possible military dimensions" of the nuclear programme.
Israel has provoked increasing speculation it is poised to launch air strikes on Iran's nuclear sites, raising the possibility of a wider conflict being triggered that could draw in the United States, EU nations, and Saudi Arabia.
Iran on Monday announced its military was holding exercises to boost air defences around its nuclear facilities.
Meanwhile, the European Union was studying Iran's positive response to an offer it made late last year to revive talks with the P5+1 that collapsed in January 2011.
EU foreign policy chief Catherine Ashton said the talks could resume if Iran placed no pre-conditions on them, particularly concerning its nuclear programme.