Deputy Foreign Minister Abbas Araghchi said the talks would be held at the deputy foreign ministerial level and that the Iranian negotiating team would hold bilateral discussions with the US and Russian delegations on January 15.
Earlier on Tuesday, Iranian Foreign Minister Javad Zarif briefed parliament, which is dominated by hardliners, in order to defend his progress during the nuclear talks. Despite tough questions by the hardliners opposed to talks, the majority of lawmakers backed the negotiating team's approach to date.
"Today nobody questions the (uranium) enrichment itself in Iran. The discussion now is on the amount of enrichment," Zarif told parliament, according to state media.
The United States, France, Germany, Britain, Russia and China reached a preliminary agreement with Iran in November 2013 for it to suspend its most sensitive nuclear activity.
Western countries in turn eased some economic sanctions imposed during the more-than-decade-long nuclear dispute.
Iran says it is enriching uranium to generate energy solely for civilian purposes. The West suspects Tehran may be trying to develop a nuclear weapon capability.
The two sides failed for a second time last month to meet a self-imposed deadline for ending the stand-off. The preliminary 2013 accord has now been extended to June 30.