The National Accountability Bureau (NAB) has prepared a corruption reference against Ashraf for the appointment of his son-in-law Azim-ul-Haq to the World Bank in violation of rules and regulations.
The decision was taken at NAB's executive board meeting which was held in Islamabad.
Ashraf was appointed prime minister in 2012 when his predecessor Yusuf Raza Gilani was disqualified by the Supreme Court for disobeying the judiciary.
During his short stint in power, Ashraf was accused of misuse of funds and authority, including appointing his son-in-law to lucrative posts.