May el-Sallab, an Egyptian women right's activist who attended the protest, told Al Jazeera: "This move shows the flawed nature of Egypt's legal system because the vote is unconstitutional as it contradicts article 40 of the Egyptian constitution.
"The kinds of people representing Egypt's legal system obviously do not want women to be part of the decision-making process," she said.
El-Sallab said: "How can we talk about justice when those implementing the law choose to discriminate against women?"
According to article 40 of Egypt's constitution: "All citizens are equal before the law. They have equal public rights and duties without discrimination between them due to race, ethnic origin, language, religion or creed."
The country's supreme judicial council, which has jurisdiction over criminal and civil courts, selected 31 women in 2007, who were later appointed by presidential decree.
But the decision angered conservatives who said women were not suited for the role.
Up until 2007, Egypt had only one woman serving as a judge who was appointed by Hosni Mubarak, the president, to the constitutional court.
Azza Kamal, a leading Egyptian women's rights activist who also attended the protest, told Al Jazeera: "This is a very discriminatory act and it will carry a rippling effect onto Egypt's culture because it tells society that women do not know how to handle roles associated with so much responsibility.
"In that sense, we, as women's rights activists, are losing the battle, we are losing the war to change minds and the present stereotypes that prevent us from gaining the rights that we are now being told to stay away from," she said.
Hossam Bahgat, an expert on human rights law and director of the Egyptian Initiative for Personal Rights, also criticised the judges' decision.
"I'm disappointed to see that there is a deep-seated bias prevalent among judges against women," he said.
Bahgat said the decision could technically be overruled by the Special Council, a supervisory body that oversees the Council of State.