Fresh concerns have been raised about Egypt’s judicial system, after officials refused to reinstate dozens of young prosecutors who were sacked because their parents lacked a university education.

Just months after they were appointed, 138 new prosecutors were removed from office in September 2013 following a ruling from the judiciary’s governing body that said only those born to parents with undergraduate degrees could join the state prosecution.

The sacked prosecutors – mostly law graduates who left university last summer – accuse the judiciary of classism, and of infringing both Egypt’s constitution, which bans discrimination, as well as international labour laws. A year on, after failing to overturn the decision in the courts, they have asked for the intervention of the president, Abdel Fatah al-Sisi, whose parents did not attend university.

The deadlock is “a disaster to social justice”, Mohamed Kamal-Eddin, one of the excluded prosecutors, told Ahram Online, the English-language version of Egypt’s flagship state newspaper. “This condition is a punishment to the parents for not having received university education. Judges are supposed to be the guards of justice. It is absurd that they decide such a condition.’’

The justice ministry declined to comment when contacted by the Guardian. So did two spokesmen for the 138 prosecutors, saying the issue was an exclusively Egyptian matter that should not interest foreign media.

Speaking on Egyptian television, a senior judge and former member of the board that banned the prosecutors said the decision was aimed at upholding the quality of the judiciary. “We have nothing against the job of garbage collectors, but their sons belong in other fields than the judiciary, because it’s a sensitive job,” said Justice Ahmed Abdelrahman.

The conflict is the latest in a string of cases to overshadow Egypt’s legal system in recent months, including the politicised trial of three al-Jazeera journalists jailed in June.

Egypt’s judiciary has been criticised for allowing what amounts to the arbitrary detention of tens of thousands of political prisoners, hundreds of whom are held in a secret prison north-east of Cairo. In one notorious case, hundreds were sentenced to death in a single day this April, in two consecutive court cases that lasted just two sessions each.

“The trials themselves are a death sentence to any remaining credibility and independence of Egypt’s criminal justice system,” said Amnesty’s Egypt researcher, Mohamed el-Messiry, at the time.

Egypt’s government insists that its judiciary is independent and impartial, and that the country is governed by the rule of law.