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.
Millions of Getty images now available for free via embed tool
Ray Liotta sues skin care company over use of likeness