The court also ordered the release of Mubarak's two sons Alaa and Gamal, pending investigations in other cases.
During the session, aired live on state television, presiding judge Mahmoud Kamel al-Rashidi stressed the case would be run in a fair manner.
Rashidi said that to ensure the proper execution of justice, he would be introducing further restrictions on who could attend Mubarak's retrial proceedings, the Egypt Independent reported.
Egypt's ousted leader Mubarak is standing retrial over charges of murdering protesters and abuse of power.
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A host of local and international reporters were also present at the gates of the police academy as clashes erupted between Mubarak supporters and victims' families.
Security forces quickly intervened to calm the unrest.
Mubarak, along with ex-Interior Minister Habib al-Adly and 6 other security officials, face charges of killing protesters during the January 2011 uprising which ended Mubarak's 30-year grip on power.
His sons along with fugitive businessman Hussein Salem, also stand trial before the same court over multiple charges of abuse of power and financial corruption.