Josef Fritzl said he "deserves credit" and was "not a monster" because he kept his daughter imprisoned in the cellar of his Austrian house when he could have easily killed her.

“I am no monster,” Fritzl said though his lawyer Rudolf Mayer, according to the German tabloid newspaper Bild.

“I could have killed all of them, and no one would have known. No one would have ever found about it.”

Fritzl remains jailed under high security Wednesday for allegedly keeping his adult daughter locked in a secret basement dungeon and sexually assaulting her for 24 years.

Fritzl locked his daughter Elisabeth, 42, beneath his house and fathered seven children with her. Three of the children – Kerstin, 19, Stefan 18, and Felix, five – had not seen sunlight until they were released by police last month after Kerstin was taken to hospital with an undiagnosed illness.

The Times of London said the statement, which was carried Wednesday by the German tabloid Bild, went on to decry what Fritzl said was one-sided coverage of the sensational story.

His lawyer is trying to get a certificate of insanity for his client, in order to be able to declare him unfit to stand trial.

Fritzl's attorney said the Amsterdam resident was a "broken man" who belonged in a mental hospital rather than prison.

Reinhard Haller, a leading forensic psychiatrist in Austria, disagreed with claims that Fritzl was insane.

Dr Haller said: “His main motivation was the exercise of power. It is not a sign of mental illness, but rather of an extreme personality disorder.”