Mubarak, who was arrested in April 2011, had been on house arrest at a military hospital since a court ordered his release in August, Ahram Online reported.
His lawyers claim his house arrest ended when the state of emergency and a curfew ended Tuesday.
That claim has been disputed. Prime Minister Hazem el-Beblawi said last week Mubarak would return to prison after the state of emergency was lifted because a law regarding pre-trial detention periods had been amended.
Legal experts contend authorities cannot extend Mubarak's detention.
Mubarak is being retried on charges of complicity in the deaths of protesters during a revolt that pushed him from office in January 2011. He also faces trial in three corruption cases.