A teenage girl has been taken to hospital with a head wound, after gatecrashers threw a house brick into the backyard of a home at Charlestown overnight.
Just before 8pm, police were called to a party on Roslyn Street after a group of uninvited people attempted to gain entry.
As the gatecrashers left, they threw bottles, sticks and a house brick into the backyard.
Police believe the brick struck an 18-year-old girl in the head, requiring her to be taken to John Hunter Hospital where the head wound was treated.
Police are appealing to anyone who has information about the gatecrashers or phone vision of the incident to contact them.