Algeria's judiciary has pursued various graft allegations against the 82-year-old since 2013, with another 20-year jail term already upheld last June for a separate case.
Chakib Khelil headed the energy ministry of Africa's top gas exporter for a decade under President Bouteflika, who stepped down in 2019 following mass protests against his 20-year rule.
The court also confirmed an international arrest warrant against Khelil, who quit his post in 2010 and moved to the United States after being implicated in a scandal involving high-ranking Sonatrach officials who were later jailed for corruption.
In 2013, the North African country issued an international arrest warrant for Khelil over a case involving contracts between Sonatrach and foreign companies, including Saipem, a former subsidiary of Italian energy giant Eni.
He returned to Algeria in 2016 after the charges were dropped, only to flee again after Bouteflika's 2019 resignation, which sparked a string of investigations into official corruption during his time in power.