A government official said he expected the premier's protection to be tightened after an emergency meeting of security officials.
Berlusconi, 73, was rushed to the San Raffaele hospital in Milan with his face covered in blood after the attack in the northern Italian city Sunday afternoon.
Police first said it appeared the assailant had punched Berlusconi in the face while clutching a souvenir statue of Milan's Duomo, the Gothic cathedral that is a symbol of the city. But state TV later showed a video, somewhat blurry, of what appeared to be the attacker's hand coming close to Berlusconi's face while holding the statue, then letting go of the object at the last minute as it hit the premier's face.
The attacker, a 42-year-old man with a history of psychological problems, has been arrested. After a night of questioning at a police barracks, the man was moved to the San Vittore prison in Milan, the ANSA news agency said. Police have identified him as Massimo Tartaglia.
The premier lost a lot of blood and is taking antibiotics and drugs for "persistent" pain, the hospital said at midday. His vital signs are normal and he is eating with difficulty but will not need surgery, his doctor, Alberto Zangrillo, said.
Berlusconi's spokesman said the premier is tired and has a strong headache
"We try to keep him at rest. He would like to re-immerse himself into his frantic activity, but doctors say caution is necessary," Paolo Bonaiuti told Italian media.
The premier asked to see read newspapers upon waking up at the hospital Monday and was visited by aides, Bonaiuti said.
Berlusconi is entangled in a sex scandal and faces criminal trials in Milan after an immunity law was overturned earlier this year. He has faced protests, with tens of thousands marching in Rome on Dec. 5 to demand his resignation.
Berlusconi himself has launched vehement attacks at the judiciary, saying the magistrates who put him on trial are politically motivated.
"Staring at his bloodied hand, he told me: 'There's a climate of hatred, I expected this would happen,'" Zangrillo told Corriere della Sera, Italy's leading newspaper.
Security officials were planning to meet in Milan to discuss responses to the attack. The undersecretary to the Interior Ministry, Alfredo Mantovano, told the ANSA news agency that he expected security measures to be tightened.