Two teenage sisters who recruited vulnerable homeless girls into a child prostitution ring and made them have sex with 'fat old men' in carparks and grotty motels have been jailed.

The pair ran their brothel from a housing unit in Warwick Farm, west Sydney for three years since they were 16 and 19.

Through Facebook or mutual friends, they lured seven vulnerable girls aged 12 to 16 with the promise of shelter and drugs such as ice.

Two teenage sisters recruited vulnerable homeless girls into a child prostitution ring and made them have sex with 'fat old men' in carparks and grotty motels. Pictured: Police take the sisters into custody

The young girls were told to put on heavy make up so they seemed older and encouraged to have sex with men in hotel rooms that the teenage sisters rented out.

Some of the girls were pimped out for the price of a pack of nappies needed for one of the sister's children.

The pimps threatened to kick them out on to the streets if they stopped work, the Daily Telegraph reported.

Sick: Father of six Bassam Darwich, 57, was convicted of using the child prostitutes

One 13-year-old who had sex with three men in three days told NSW District Court: 'I was so alone. I still live in fear of being kicked out into the streets, having nowhere to go and no one to love me.'

Three men were convicted of using the child prostitutes: Rino Mura, 58, Bassam Darwich, 57, and Trevor Weger, 56.

One of Darwhich's victims 'lay there crying ... placing the pillow over her face until the sex had finished'. The crane operator was jailed for three years and six months.

Weger was jailed for three years and accountant Mura will be sentenced on Friday.

The brothel was discovered when Mura called police after he was robbed at gunpoint in February 2012.

Detectives felt something more sinister was going on and decided to investigate further.

They found out Mura was with a 13-year-old prostitute who had been advertised as 'very pretty, size 10, big boobs, black hair' when he was robbed in a set up by the teenage sisters.

Through Facebook or mutual friends, the pimps lured seven vulnerable girls aged 12 to 16 with the promise of shelter and drugs such as ice. Pictured: One of the sisters is taken in

The sibling pimps - whose IQs are among the lowest one per cent in Australia - were brought up by their grandmother because their mother, who was addicted to heroin, spent most of their lives in jail.

The oldest sister, who has three children in care, was jailed for eight years after pleading guilty to 21 counts of child prostitution.

Her younger sister was jailed for six years and 10 months after pleading guilty to 10 counts of the same charge.

Judge Martin Blackmore said: 'Children are entitled to the protection of the law even when they are not protecting themselves.'