Vulnerable girls as young as 12 were used as a personal ATM by alleged child prostitution ring leader Tahlia Garner to feed her desperate addiction to the drug ice, a court has heard.

Ms Garner, 22, and her older sister Adrienne, 24, are charged with selling four teenager girls to middle-aged men for sex in their home and hotels in Sydney's southwest between August 2010 and January 2012.

On Tuesday, the Sydney District Court heard the Garners allegedly preyed on young girls between 12 and 17 who were homeless, runaways or in the care of community services by providing them with money, accommodation and methamphetamines before selling them for sex.

Crown Prosecutor Rossi Kotsis said the sisters prostituted themselves to buy drugs and ''whenever the drugs ran out they would use vulnerable girls as young as 12 as ATMs''.

In applying for bail, Tahlia's barrister, Cara Feiner, argued her client had been in custody since her arrest in May 2012 and will have served about two and a half years on remand by the time her eight-week trial is scheduled to begin in September.

Ms Feiner said if granted bail, Tahlia would receive Centrelink benefits and could live with two associates or in a women's refuge.

But Judge Helen Syme refused bail, saying that as the people she proposed living with had lengthy criminal records and a history of drug use, such a move would be ''foolish''.

Allowing Tahlia to live in a refuge would also be a ''silly idea'' given she would have access to girls in a similar situation to those she allegedly recruited to the prostitution ring.

The Court heard Tahlia's mother, who was in the public gallery to support her daughter, also used ice and is due to appear in court on Wednesday where she faces a likely jail term for related charges.

Judge Syme said Tahlia ''has had precious little guidance and support from her family in the past'' and has proven to be a ''resilient young woman'' who is ''capable of surviving on the streets''.

But she said such qualities meant she was too high a flight risk to be granted bail and some of the charges carried a minimum 10 year non parole period.