The US has charged that the site is involved in nuclear weapons work.

Iran's Islamic Republic News Agency reported on Thursday that the inspection of Parchin could take place "within a few days" of the discussions, which will be on Friday.

On Wednesday, International Atomic Energy Agency (IAEA) director Muhammad al-Baradai announced that Iran had finally given the green light for his inspectors to investigate Parchin, a huge complex 30km southeast of Tehran.

The US says the Iranians may be working on testing "high-explosive shaped charges with an inert core of depleted uranium" at Parchin as a test for how a bomb with fissile material would work.

The IAEA has been seeking access to Parchin since July.

Tehran has strongly denied carrying out any nuclear-related work at the site and insists its nuclear effort at other sites is aimed at generating electricity.

Parchin is an example of a transparency visit, where the IAEA is going beyond its mandate under the nuclear Non-Proliferation Treaty to see whether nuclear materials have been diverted from peaceful use.