Said Bouteflika, widely seen as the real power behind the presidency after his brother suffered a debilitating stroke in 2013, went on trial on Monday alongside two former intelligence chiefs and a political party head.

All four face allegations of "undermining the authority of the army" and "conspiring" against the state in order to bring about regime change, in the run-up to the ageing president's resignation in the face of mass protests earlier this year.

On Tuesday, prosecutors at the military court in Blida, south of Algiers, "asked for the maximum sentence of 20 years against all the defendants", defence lawyer Miloud Ibrahimi said.

He said the verdict was expected "on Wednesday or Thursday at the latest".

Former defence minister Khaled Nezzar has alleged that as protests mounted against the veteran leader, Said Bouteflika met with the other defendants to discuss declaring a state of emergency and firing army chief General Ahmed Gaid Salah.

Lawyers for Workers' Party chief Louisa Hanoune have admitted she met the president's brother and General Mohamed Mediene on March 27, a day after Gaid Salah publicly called for the ailing president to step down.

Said's detention in May along with Mediene, who headed the all-powerful secret service for 25 years, and fellow ex-spy chief General Athmane Tartag -- also alleged to have been at the meeting -- was part of a wave of arrests targeting the ousted president's inner circle.

The hearings have been restricted to lawyers and defendants' families only, with media also kept out of the courtroom.

Mediene, whose health has been deteriorating according to his family, arrived in court in a wheelchair and asked for an adjournment, according to defence lawyers. The judge consulted a doctor and turned down the request.

Known as Toufik, Mediene headed the all-powerful DRS intelligence agency from its foundation in 1990 up to his fall from grace in 2015.

Tartag, his deputy, succeeded Toufik and when the DRS was dismantled in 2016 he served as Algeria's security coordinator under the supervision of the presidency.

A string of prominent politicians and businessmen have been questioned or detained over alleged graft since Bouteflika resigned in April after two decades in power in the face of mass protests.

Presidential elections have now been set for December 12, but protesters have kept up their demands for political reforms and the removal of the former president's loyalists, including army chief Gaid Salah, who has emerged Algeria's strongman since Bouteflika's fall.