It is not clear when the party will be officially formed. Attempts to reach Salah Eddin were unsuccessful Saturday night. There was no immediate response from the ruling party.
Salah Eddin has a support base among young Islamist youths, university students in Khartoum and other cities, and many in the country's elite.
The September riots in some places turned into a call for the ouster of al-Bashir, who has ruled the country for more than two decades. Sudan lost most of its main oil-producing territory when South Sudan broke off and became an independent state in 2011. That came after a civil war plagued the country for decades.
Al-Bashir is wanted by the International Criminal Court on allegations linked to the conflict in Sudan's western region of Darfur, where an estimated 300,000 people have died since 2003 due to fighting between government-backed tribes and rebels.