MELBOURNE, June 30, 2009 (AFP) - An Australian serial rapist who dressed his unconscious victims in his collection of women's underwear and filmed assaults on them was Tuesday jailed for 28 years.

Victorian Supreme Court Chief Justice Marilyn Warren said John Xydias, 45, had degraded women in a spree lasting 15 years which media described as one of the country's worst sex crimes.

"Your offending was sustained over a period of 15 years, your conduct was not low-level or less-serious rape," Warren said.

"The worst aspect of your conduct was the degrading and dehumanising of your victims."

Xydias showed little emotion as the sentence was read out. He pleaded guilty to 25 counts of rape and 61 indecent assaults at the Melbourne house he shares with his parents and at the family holiday home.

The crimes were discovered when Xydias's girlfriend handed a suspicious DVD to police, who searched his home and found 13 videos of his sex assaults as well as recording equipment and women's underwear.

Xydias denied doping his victims with date-rape drug Rohypnol and said they had fallen unconscious after drinking and smoking cannabis. The court earlier heard that one of the women had been unconscious for two days.

Xydias will serve a minimum of 20 years before being eligible for parole.