The victim – a 17-year-old disabled girl – had reportedly been lured there and believed she was meeting up with her boyfriend.
During the horrific attack - which was filmed on a mobile phone and shared to Facebook - the girl was allegedly forced to inhale glass, her hands were burned on a barbecue and her head was slammed into a wooden picnic table several times.
Her devastated mother told Ten that her daughter was left ‘black and blue’.
'She's unrecognisable. She can't put her glasses on because her cheekbones are so swollen,' she told Ten News.
The girl was taken to hospital where she was treated for serious facial injuries.
Three girls – two aged 15 and one aged 12 - have been charged with assault and robbery.