Judge Mahmoud el-Rachidi said the sessions, to be held on October 19-21, would involve national security issues.
Hosni Mubarak, 85, appeared in court on charges of complicity in the killing of protesters during the 2011 uprising.
Defense lawyers are seeking to blame Islamists from the Muslim Brotherhood and foreign forces for the deaths of about 850 people killed in the unrest.
Hosni Mubarak was jailed for life in June last year for contributing to the killings.
But he appealed against his sentence and a retrial was ordered.
Hosni Mubarak is on trial along with his two sons, the former interior minister, and six security chiefs.
Certain parts of his original trial were also held behind closed doors.
Judge Mahmoud el-Rachidi had promised more transparency with the retrial.
However, the judge said on Saturday that all journalists would be barred from the next hearings and forbidden from quoting lawyers.
“This decision does not go against my previous promise to the media, because I had announced from the start that the people will know about everything, except for proceedings of hearings, in order for us to allow the witness to testify,” he said.
The interior minister’s lawyer said the people called to testify had information on who killed the protesters, and “which foreign factions joined forces with the Muslim Brotherhood in the events of the 28 January [2011] to cause chaos and the killing of protesters”.
Muslim Brotherhood’s candidate Mohamed Morsi won Egypt’s first free election last year, but was eventually overthrown by the military after widespread protests.
Hosni Mubarak was freed from custody shortly after the overthrow, and placed under house arrest.
During Hosni Mubarak’s 29-year rule the Muslim Brotherhood was outlawed.
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