St Poelten, Austria - Josef Fritzl appeared in court for a second day on Tuesday as the jury heard further testimony of how he imprisoned and raped his daughter over a period of 24 years, fathering seven children by her.

The court was due to hear taped evidence from Fritzl's daughter, Elisabeth, 42, describing her ordeal and the birth of her children in a windowless cellar beneath the family home.

Fritzl, 73, hid his face behind a blue folder as he entered the courtroom clad in a grey jacket and dark trousers, just as he did on Monday. He refused to speak to journalists, who were then ushered from the court as proceedings began behind closed doors.

At the opening of the trial on Monday, Fritzl pleaded guilty to seven counts of incest, rape and false imprisonment, but denied the murder of one of the children, who died shortly after birth.

Fritzl, whose arrest in April 2008 brought worldwide notoriety to the small Austrian town of Amstetten, also denied a charge of enslavement.

Elisabeth disappeared in 1984, when she was just 18. Fritzl kept her in the airless dungeon without the knowledge of the rest of his family.

Four years later, Elisabeth's daughter Kerstin was born and remained incarcerated in the cellar with her mother. Of the subsequent six children, two more remained below ground, where they were permanently deprived of daylight.

Three children, whom Fritzl claimed were abandoned on his doorstep, were then raised in the family home upstairs by Fritzl and his wife. One child, a twin, died shortly after birth.

Eleven hours of pre-recorded testimony by Elisabeth were being shown to the court in small segments. The first part was shown Monday but no details emerged of the content or Fritzl's reaction.

The jury - consisting of six men and six women - is expected to reach a verdict on Thursday or Friday.

If convicted of enslavement, Fritzl could face a maximum 20 years in jail. Rape carries a maximum 15-year sentence under Austrian law.

Elisabeth and her children are currently staying at the clinic in Amstetten where they spent several months after Fritzl's crimes were discovered when he took his eldest daughter to hospital for treatment of a mysterious illness.

The family had been given new identities. But paparazzi discovered their whereabouts, prompting them to leave their new home. (dpa)