Austrian Josef Fritzl said he became addicted to incest with his daughter, who bore him seven children and had imprisoned her in a cellar to save her from the outside world.
In comments related by his lawyer to weekly magazine News, Fritzl, who locked up Elisabeth in 1984 when she was 18, said he started raping his daughter a year later.
"My drive to have sex with Elisabeth grew stronger and stronger," Fritzl was quoted as saying.
"I knew Elisabeth didn't want me to do what I did to her. I knew that I was hurting her ... It was like an addiction ... In reality, I wanted children with her."
Elisabeth, 42, spent nearly a quarter of a century in a windowless cell in the basement of Fritzl's house, giving birth to seven of his children, now aged between 19 and five years.
Three of the children remained locked up with their mother in the basement and never saw sunlight until their fate was revealed nearly two weeks ago. Elisabeth has told police that Josef started sexually abusing her when she was 11.
Fritzl, who also has seven children with his wife Rosemarie, said he had locked up Elisabeth after she started to "break all the rules" following the onset of puberty.
She went to bars, drank alcohol and smoked and ran away a couple of times, the 73-year-old said.
"I tried to get her out of that swamp, organised her an apprenticeship to become a waitress.
"I needed to take precautions, I needed to create a place in which I could at some point keep her away from the outside world, by force if necessary."
Fritzl said he found himself trapped in an inescapable cycle once he had locked up Elisabeth. He told his wife their daughter had joined a sect.
"I knew all the time, during the whole 24 years, that what I did was not right, that I must be crazy to do something like that," he said, referring to Elisabeth's underground world as his "empire".
"But nonetheless, it became a matter of course for me to lead a second life in the basement of my house."
Fritzl's lawyer, Rudolf Mayer, has said his client should have psychiatric tests to evaluate whether he is fit to stand trial. Mayer said he might ask for a second assessment should the official court opinion not reflect his client's personality.
Fritzl described himself as a man who valued decency and good manners and said the emphasis on discipline in Nazi times, when he grew up, might have influenced him.
"Nonetheless, I am not the beast the media depicts me as.
"When I went into the bunker, I brought flowers for my daughter and books and toys for the children and I watched adventure videos with them while Elisabeth was cooking our favourite dish," he said.
"And then we all sat around the table and ate together."
Fritzl has been remanded in custody in the city of St Poelten. Mayer confirmed to Reuters that Fritzl's comments were authentic.
