An Algerian military court Sunday started hearing an appeal against the 15-year jail term for the brother of former president Abdelaziz Bouteflika, who was brought down amid anti-regime protests last year.

Said Bouteflika, 62, had long served as a key presidential aide and was seen as the real power behind the presidency after the head of state suffered a debilitating stroke in 2013.

Abdelaziz Bouteflika quit office in April last year following weeks of mass protests against his bid for a fifth term running the North African country.

His brother Said was detained in May and sentenced in September, along with several other high-level regime officials, to 15 years in jail for "conspiring" against the state and undermining the authority of the army.

The appeals hearing opened in the mid-morning under tight security and behind closed doors at the Military Court of Appeal in Blida, south of Algiers, according to local media.

Also in court to appeal their jail terms were two former intelligence chiefs and a former political party leader.

One was General Mohamed Lamine Mediene, known as "Toufik", who had for 25 years headed the powerful Department of Intelligence and Security.

Also there were his former right-hand man, General Athmane "Bachir" Tartag, and Louisa Hanoune, who had served as secretary general of the left-wing Workers' Party.

All four had allegedly met in March 2019 in a bid to derail plans by the army high command to force the departure of president Bouteflika.

Said allegedly wanted the intelligence bosses to dismiss the army chief of staff at the time, General Ahmed Gaid Salah.

Defence lawyers hope the four will be released after Algeria's power balance shifted following the December 23 death of Gaid Salah at the age of 79.

"The person who, in our opinion, was at the origin of these proceedings has passed away." said Mediene's lawyer Farouk Kessentini.