Iran will not talk about its "nuclear dossier" at the Istanbul talks with world powers, atomic chief Ali Akbar Salehi said in comments published Wednesday, reiterating Tehran's long-standing policy.

"We will absolutely not recognise the negotiation if the other side wants to negotiate on the issue of the nuclear dossier" of Iran, Salehi, who is also acting foreign minister, said in an interview with state-run Iran newspaper.

"The technical and legal aspects of any country's nuclear issues can be discussed only with the International Atomic Energy Agency and the agency, based on international rules and regulations, is the only authority to judge the member states' issues," he added.

"If we consider this as the principle... then discussing the issue, named (Iran) nuclear issue, from our point of view is a dossier fabricated by the West and discussing it with the five-plus-one about this is meaningless," said Salehi, who oversees Tehran's nuclear programme.

His remarks come ahead of a January 21-22 meeting in Istanbul between Iran and the six world powers -- Britain, China, France, Russia, the United States and Germany -- aimed at resolving a dispute over Iran's nuclear programme, which the West fears masks a weapons drive but which Tehran insists is entirely peaceful.

Top Iranian officials, including President Mahmoud Ahmadinejad, have maintained that Tehran's nuclear dossier is a "closed file."

Prior to previous talks with the world powers, Tehran has similarly insisted that its nuclear file is not up for discussion.

Salehi said it had been decided in the previous round of negotiations held in Geneva on December 6 and 7 that only "the common points" shared by the two sides would be discussed.

These, he said in the interview, included discussions over security, economy, nuclear disarmament, non-proliferation and nuclear cooperation.

The West has insisted that the talks with Iran should focus on its nuclear file, especially the uranium enrichment programme, the most controversial aspect of its atomic programme.

Foreign ministry spokesman Ramin Mehmanparast said on Wednesday that "nuclear experts" were welcome to join a tour of Iran's atomic sites planned ahead of the talks.

"This invitation was a confidence-building measure ... and considering the opinions of the guests, we announce that it is no problem to bring nuclear experts on this visit," the official IRNA news agency cited him as saying.

Iran said last week that invitations to visit its nuclear sites at Natanz and Arak had been sent to ambassadors of some of the nations who are members of UN nuclear watchdog the International Atomic Energy Agency.

In a separate report, Iran's IAEA envoy said that representatives from allies Venezuela and Syria would also join the Saturday-to-Monday visit.

Under Ahmadinejad's presidency, Iran has refused to abandon the enrichment programme as demanded by the West, saying it is a "nuclear state" and gaining nuclear technology is an "inalienable right."

Iran has been slapped with four sets of UN sanctions for pursuing the uranium enrichment programme.

Several other countries, including the United States, as well as the European Union have imposed their own unilateral sanctions on Iran in a bid to halt the Islamic republic's nuclear programme.

The United States and its ally Israel have not ruled out taking military action against Iran to prevent it from acquiring nuclear weapons.