No timetable was given for the review, but even the consideration of releasing Mir Hossein Mousavi and Mahdi Karroubi suggests further moves at political reconciliation under new President Hassan Rouhani.
Since last month, officials have freed more than 90 people jailed in crackdowns since huge unrest after the disputed re-election of Rouhani's predecessor, Mahmoud Ahmadinejad, in 2009. Candidates Mousavi and Karroubi led those protests.
Government spokesman Mohammad Bagher Nobakht was quoted today by the semiofficial Fars news agency as confirming the cases are under study.