Seven people have been arrested and charged with more than 100 sexual and physical abuse offences against three boys from 2014 to 2016.
The alleged offences – 127 in total – include aggravated sexual assault, kidnapping, and possessing child abuse material.
The boys were aged under eight at the time the alleged offences took place, and were known to the people who have been charged, police said.
Four women, two men and one teenage girl were arrested at homes in Katoomba, Canterbury and Wentworthville on Monday. Local media have reported that the seven people are linked to a circus school.
The lawyer for all seven accused, Bryan Wrench of Murphy's Lawyers, said his clients intended to plead not guilty on all charges.
All seven remain in custody after appearing in court on Tuesday.
Three people aged 17, 18 and 20 appeared at a children's court.
A 17-year-old girl was charged with eight counts of aggravated sexual assault in company, aggravated kidnapping, and producing child abuse material.
An 18-year-old Katoomba man was charged with 42 offences, including kidnapping, sexual intercourse with a child under 10, and common assault.
A 20-year-old Canterbury woman was charged with offences including aggravated sexual assault, aggravated kidnapping, and assault.
A 58-year-old Katoomba woman, a 26-year-old Katoomba woman and a 52-year-old Katoomba man appeared at Penrith Local Court.
The 58-year-old woman has been charged with 43 offences, including aggravated sexual assault of a child under 10, having sexual intercourse with a child under 10, and aggravated kidnapping.
The 26-year-old was charged with 13 offences, including aggravated sex assault in company.
The 52-year-old man was charged with offences including aggravated sexual assault in company with a child under 10 and using a child under 14 to make child abuse material.”
A 29-year Canterbury woman also appeared at Burwood Local Court, charged with five counts of aggravated sexual assault in company and three counts of common assault.
NSW police said the investigation was carried out by Strike Force Baillieu, established by detectives from the Child Abuse and Sex Crimes Squad in July 2017.
The accused will next come before the courts for a bail release application hearing on February 16.