Algerian judges and prosecutors began an open-ended strike to demand the independence of the judiciary after a massive reshuffle that has affected thousands, the union of magistrates said.

The move comes as the country remains wracked by anti-government protests against a planned December presidential election that must be overseen by judges.

Earlier this month the justice ministry carried out an unprecedented reshuffle of the judiciary in a move that affected 3,000 judges and prosecutors, out of around 6,000.

The National Magistrates' Syndicate (SNM) denounced the move as "a stranglehold by the executive over the power of the judiciary".

It accused the government of "encroaching on the prerogatives of the Supreme Judicial Council", it said in a statement.

Activists are demanding sweeping reforms in the oil-rich country before any vote takes place, and say Bouteflika-era figures still in power must not use the presidential poll as an opportunity to appoint his successor.

The Hirak protest movement was formed in February to demand that Bouteflika resign instead of running for a fifth term, and has been backed by Algerians from all walks of life, including lawyers and judges.

Polls originally planned for July 4 were postponed due to a lack of viable candidates and in April Algeria's magistrates had said they would boycott that election.

The country has an interim president, Abdelkader Bensalah.

Algeria's electoral committee has registered 22 candidates for the December polls, including two former prime ministers who served under Bouteflika.