President Jalal Talabani told Iraqi television on Tuesday that he had been informed by an investigating judge that "he (the judge) was able to extract confessions from Saddam's mouth".
Talabani said the ousted leader had spoken about crimes "as executions" which he had personally ordered.
Iraq's new president said some of the confessions involved cases actively under investigation but he did not specify them.
Saddam Hussein faces his first trial on 19 October for his alleged role in the massacre of Shia Muslims in Dujail, a town north of Baghdad, in 1982.
The former president could face the death penalty if convicted.
The Iraq Special Tribunal is also investigating Saddam's role in other atrocities, including the 1988 gassing of thousands of Kurdish civilians in Halabja and the 1991 suppression of the Shia rebellion in the south.
Iraqi authorities plan to try those cases separately.
Deserves hundred deaths
Saddam Hussein is facing charges
of crimes against humanity
Despite his own public opposition to the death penalty, Talabani told Iraqi television: "Saddam Hussein deserves to die 100 times."
Defending the trial, the president said: "No political decision to eliminate Saddam Hussein has been taken and the judiciary is independent.
"If he had fallen into our hands during the war we were waging then we could have eliminated him, but now we have to put him on trial," he added.
Talabani's interview was aired late at night and no other officials or the Iraqi tribunal have made further comment.
However, Abdel Haq Alani, a legal consultant to Saddam's family, condemned Talabani's remarks and said the alleged confession "comes to me as a surprise, a big surprise".
"I have heard nothing whatsoever about this alleged media speculation," Alani said in Amman, Jordan.
"This is a matter for the judiciary to decide on, not for politicians and Jalal should know better than that.
"Why should he make a statement on the accused to the public? The court, the judge need to decide on this."
He said Saddam made no mention of any confession when he
met his Iraqi lawyer on Monday.
"Is this the fabrication of Talabani or what? Let's not have a trial on TV. Let the court of law, not the media make its ruling on this," Alani said.