Scuffles broke out between lawyers and security personnel outside a New Cairo courthouse as the session of activist Ahmed Doma, accused of insulting the president, was about to start.
Security allegedly did not allow the attorneys to enter the courtroom Monday afternoon and arguments escalated.
Dozens of members of the influential April 6 Youth group converge outside the courthouse in solidarity with the activist.
Doma, a vociferous critic of the Muslim Brotherhood – from which President Morsi hails - was arrested late in April by state prosecutor order after he called President Morsi a "killer" in a television programme.
Opponents of the Islamist group accuse President Morsi's government of using such arrests to intimidate its opponents.
Security measures have been beefed up around the court, which is also hearing the case against six persons accused of pertaining to Black Bloc, radical black-clad youth groups that recently emerged against the Brotherhood.
The defendants face charges of violence and damaging public property.