The experts are scheduled to gather in New York to prepare the ground for the next ministerial-level negotiations in Vienna on May 13, AP reported.
Their closed-door sessions, starting Monday, are taking place on the sidelines of the third and final preparatory conference for next year's review of the landmark 1970 Nuclear Nonproliferation Treaty (NPT), a pact aimed at stopping the spread of nuclear weapons.
The forthcoming talks are expected to stretch over a week.
During the negotiations, Hamid Baeedinejad, the director general for political and international affairs at Iran’s foreign ministry, will lead the Iranian delegation.
And Stephen Clement, who is an aide to the European Union foreign policy chief Catherine Ashton, is to head the opposite negotiating team.
The ministerial-level meeting, slated for May 13, will convene in Austria in the presence of political directors from Iran and the six other nations.
In the upcoming round of high-profile talks, the negotiating parties will start drafting the text of an ultimate agreement to end the decade-long standoff on Iran’s nuclear case.
The two sides on November 24, 2013, clinched an interim six-month deal in the Swiss city of Geneva.
The breakthrough deal (the Joint Plan of Action), which has come into effect since January 20, stipulates that over the course of six months, Iran and the six countries will draw up a comprehensive nuclear deal which will lead to a lifting of the whole sanctions on Iran.