Germany's former chancellor Gerhard Schroeder will arrive in Tehran on Sunday with a large business delegation, ISNA news agency reported.
Schroeder will also hold political talks, ISNA said, with a meeting planned Monday with the head of the National Security Council, Ali Shamkhani.
The visit was originally scheduled for November, but postponed because of the death of former German chancellor Helmut Schmidt.
Schroeder, who was chancellor from 1998 to 2005, made a private visit to Iran in February 2009 at the invitation of a friend, Majid Samii, an Iranian neurosurgeon and acquaintance from his hometown of Hanover.
While that trip was made to open a scientific foundation in northern Iran, he also met the country's political elite, including then president Mahmoud Ahmadinejad and former president Mohammad Khatami.