A Cairo misdemeanor court on Saturday adjourned the trial of 23 protesters arrested at June demonstration to 11 October.
The defendants include rights activist Sanaa Abdel-Fattah, photojournalist Abdel-Rahman Mohamed who works for Al-Badil news site, human rights lawyer Yara Sallam, and photographer Rania El-Sheikh.
The activists are to remain in detention until their next court session.
The protesters were in the process of marching to Ittihadiya presidential palace when they were arrested. They were demonstrating against a new law, issued in 2013, which bans public protests unless they have been pre-approved by police and gives security forces the right to bar any public gathering of more than ten people.
Hundreds of people, including several prominent activists, have been charged and convicted under its provisions.
Many friends and activists were outisde court on Saturday to show support for the detained protesters.
At least two of the defendants, Abdel-Fattah and Mohamed Youssef, have joined an ongoing campaign of hunger strikes by a group of detainees who allege that their charges and convictions are political.
Around 66 detainees have joined the strike, as have many supporters. Seven leftist and liberal political parties declared on Friday that they would also be joining the hunger strike temporarily in solidarity.
The campaigners are calling for the release of all prisoners and detainees in cases involving freedom of opinion, and are also demanding the protest law be amended.