Sydney teen charged after ambulance 'doused in petrol' during house party

A Sydney teenager has been charged after he allegedly doused an ambulance in petrol during a house party where emergency service workers were called to treat a 14-year-old for burns.

Volunteer firefighters were forced to call for police back-up on Saturday when party goers became aggressive.

Some party guests tried to obstruct efforts to extinguish a bonfire at the Rossmore property in Sydney’s south-west.

Police managed to move the partygoers inside the home while the fire was contained.

A 14-year-old was treated for burns to his face and taken to Westmead Children's Hospital. He remains in a stable condition.

About 1.45am a paramedic called for police assistance after he returned to an ambulance and found it had been ‘doused in petrol’.

The vehicle had been left at the scene as paramedics drove the 14-year-old to hospital in another ambulance.

Police arrested an 18-year-old man, who has since been charged with damage to property.

The teen was granted conditional bail and will appear in Liverpool Local Court on Thursday May 26.

Police have asked any witnesses who have not yet come forward or may have mobile phone footage to contact them.

NSW Ambulance Service later took to Twitter to thank police for their support.