Egyptian President Mohammad Mursi faces a rebellion from judges who accused him on Saturday of expanding his powers at their expense.

Egyptian President Mohammad Mursi faces a rebellion from judges who accused him on Saturday of expanding his powers at their expense, deepening a crisis that has triggered calls for more protests following a day of violence across Egypt.

Judges in Alexandria, Egypt's second city, threatened to go on strike until it was revoked, where Mursi's opponents and supports have called rival demonstrations on Tuesday over his decree that has triggered concern in the West.

Issued late on Thursday, the decree marks an effort by Mursi to consolidate his influence after he successfully sidelined Mubarak-era generals in August.

It also shields the Islamist-dominated assembly writing Egypt's new constitution from a raft of legal challenges that have threatened the body with dissolution, and offers the same protection to the upper house of parliament.

Egypt's highest judicial authority, the Supreme Judicial Council, said the decree was an "unprecedented attack" on the independence of the judiciary.

Mursi also assigned himself new authority to sack the prosecutor general - a Mubarak hold over - and appoint a new one. The dismissed prosecutor general, Abdel Maguid Mahmoud, was given a hero's welcome by several thousand judges who attended the session of Egypt's Judges' Club in Cairo on Saturday.

Ahmed al-Zind, head of the Judges' Club, introduced Mahmoud by his old title, in open defiance of Mursi's decree.

The Mursi administration has defended the decree on the grounds that it aims to speed up a protracted transition from Mubarak's rule to a new system of democratic government.

Analysts say it reflects the Brotherhood's suspicion towards sections of a judiciary unreformed from Mubarak's days.

Mursi is facing the biggest storm of criticism since he won the presidential election in June.

Youths clashed sporadically with police near Tahrir Square, the epicentre of the uprising that toppled Mubarak in 2011, following Friday's violence in which more than 300 people were injured across Egypt. Activists camped out for a second day in the square, setting up makeshift barricades to keep out traffic, Reuters news agency reported.