"Iran is ready to faithfully engage and remove any ambiguity on its nuclear activities," Reza Najafi, Iranian ambassador to the IAEA, said in his first speech at the UN nuclear watchdog's closed-door board meeting, Xinhua reported.
He said Tehran was ready to cooperate with the agency constructively on the nuclear issue.
Fresh rounds of talks between Iran and the IAEA are scheduled for Sep 27 here. Ten rounds of previous talks have failed to make substantial progress in the past two years.
Najafi reiterated Iran would never compromise on its "inalienable right to develop nuclear programme".
Iranian President Hassan Rohani appointed Najafi to replace Ali Asghar Soltanieh, whose relation with the IAEA was seen as a source of tension by the agency.
Najafi's appointment is seen by the West as a sign that Iran's moderate president seeks a diplomatic resolution to the decade-long nuclear dispute.
Western states have long accused Iran of developing nuclear weapons under the cover of Tehran's nuclear power plans -- an allegation Iran strongly denies and has repeatedly dismissed.