Colin Harold Doo, 51, pleaded guilty at the Supreme Court here to 36 charges including 12 counts of committing indecent acts in the presence of a child under 16, nine of producing child pornography and seven of rape. He committed the crimes between 1996 and 2008.
The former piano teacher gave food and soft drinks to his victims at his house and drugged one of his victims before raping her, the court heard. He used sex toys on his victims.
Doo befriended his victims' parents and managed to mingle into their lives, prosecutor Ray Gibson was quoted as saying by the Age.
The court also heard that footage from cameras showed the victims changing their clothes and using the toilet. He also showed pornography to a girl while giving piano lessons at her house.
In raids conducted at his house in February 2008, police seized over 1,000 CDs, 33 computer hard drives, women's and children's clothing, 58 video cassettes, 47 DVDs, five video cameras and sex toys.
Doo later told police he had burnt 10 video cassettes in a frying pan.
