The ministerial meeting opened in Astana on Wednesday at the Central Asian countrys foreign ministry with Iranian Foreign Minister Mohammad Javad Zarif in attendance.
The top diplomats had already held an unofficial meeting earlier on Wednesday.
In a separate meeting, Zarif and his Kazakh counterpart, Erlan Idrissov, had exchanged views about a range of issues, including ways to boost cooperation between Tehran and Astana in various political and economic areas.
Upon his arrival in Kazakhstan on Tuesday, Zarif had said that the Caspian countries have reached a consensus on many topics, but noted that a number of issues still remain to be settled.
It would be relatively optimistic to think that participants in the Astana meeting will be able to resolve the outstanding issues and reach a conclusion, Zarif said.
Though the differences have been widely narrowed, there still exist issues that need to discussed and settled, he added.
A special working group from Iran had arrived earlier in Astana to participate in the expert-level talks ahead of the ministerial meeting.
The working groups sessions were part of efforts to draft the convention on the legal status of the Caspian Sea.
The 45th meeting of the special working group of the Caspian Sea concluded in Russias capital of Moscow on June 10 with a communiqu.
The Caspian Sea is the largest enclosed water body on earth by area, variously classed as the worlds largest lake or a full-fledged sea.
The Caspian Sea Convention will determine the territorial rights of littoral states as well as other matters related to the world's largest landlocked body of water.
By Tasnim News Agency
