Five arrested over child prostitution ring

Police expect more arrests over a Sydney child prostitution ring. (AAP)

Police expect more arrests over a Sydney child prostitution ring. (AAP)

Police expect more arrests over a Sydney child prostitution ring whose customers paid as little as $10 to engage in sexual acts with girls as young as 12.

A child prostitution ring run by two sisters in Sydney has ballooned to include seven young girls and at least three customers, with more arrests expected.

Police raided four homes on Thursday morning in Canley Vale, Cabramatta West, Northmead and Chester Hill.

Three men aged between 51 and 53 were arrested and are assisting police. They are expected to be charged, police say.

Detectives from Strike Force Woodvale also arrested a 19-year-old woman and rearrested her 22-year-old sister, who was charged in March.

The 22-year-old was originally accused of charging men between $10 and $100 to engage in various sexual acts with two girls aged 12 and 13.

Another five girls between the ages of 12 and 16 are now believed to have been involved.

Back in March, police believed the prostitution ring had been operating between November 2011 until February this year but now say it has been operating for a minimum of two years.

Liverpool Local Area commander Ray King said he had been working as a police officer for a long time but has never been so disgusted over what detectives have uncovered.

"These are children that have been abused and manipulated," Superintendent King told reporters on Thursday.

"We don't know how they will be in 20 years. It's quite traumatic."

Police allege the sisters operated the prostitution ring in the Liverpool and Warwick Farm area and have previously said the young girls involved were vulnerable, and some may have been living on the street.

Detectives expect to charge the younger woman and three men on Thursday. They will appear in court on Friday.