A defence lawyer claims a foreigner gave him a list of witnesses to call.
Correspondents say the court hopes to complete the case before Saddam Hussein is executed following his conviction.
The former leader was found guilty of crimes against humanity for the killing of 148 people in the mainly Shia town of Dujail following an assassination attempt on him in 1982.
He was sentenced to death by hanging on 5 November, but under Iraqi law the guilty verdict is automatically sent to the appeal court.
'Lined up'
The Anfal trial resumed after a two-week break as a curfew imposed on Thursday after deadly car bombings in a Shia area of Baghdad was lifted.
Saddam Hussein and the six co-defendants face charges over their role in the 1987-88 Anfal campaign against ethnic Kurds, many of whom were gassed to death.
All seven defendants were in court, mostly represented by court-appointed lawyers, as some defence lawyers have been boycotting the trial.
The court has heard some harrowing accounts from Kurdish survivors of the operation, which they say was designed to move people from their homes, says the BBC's David Loyn in Baghdad.
The first witness of the day, Taimor Abdallah Rokhza, described how Kurdish villagers were killed.
"There was a trench there and we were lined up and a soldier was shooting at us," the French news agency AFP quoted him as saying.
"Then suddenly it stopped and it was quiet. I was waiting to die and my whole body was covered with blood, and the soldiers went away."
The testimony came as defence lawyer Bedia Araf claimed that either an American or Canadian had come to his house on Sunday night and proposed a list of 30 people to call as witnesses.
Mr Araf said the foreigner claimed to have the power to get his client released or convicted.
The judge expressed impatience, appealing to Mr Araf to provide any list of witnesses, as the court needed time to process them securely.
It is not clear if the Iraqi authorities will wait until the second trial is complete before they carry out the sentence in the first case.
Iraqi Prime Minister Nouri Maliki has said he expects Saddam Hussein to be executed by the end of 2006.