Omar Hamid, a spokesman for the interior ministry, said Abdul Ghani Baradar had been freed, The News International reported.
Hamid provided no additional details.
Pakistan's foreign ministry, in a statement Friday announcing Baradar's pending release, said the former top Taliban leader was being freed "to further facilitate the Afghan reconciliation process."
Kabul accused Islamabad of undermining peace negotiations with the Taliban when Baradar was arrested in Pakistan, where he fled following the U.S. invasion of Afghanistan in 2001, the BBC reported.
The Taliban's second in command at the time of his arrest, Baradar is viewed as one of the few top members of the movement willing to negotiate.
Baradar is one of the four men who founded the Taliban in Afghanistan in 1994.