A man has been charged with y assaulting another man with a hammer at Blacktown.
About 2.15pm on Wednesday, an 18-year-old man from a Fourth Avenue home became involved in a struggle with another man nearby.
Police will allege that the man forced his way into a nearby unit, attacking a 23-year-old man with a hammer.
The injured man, who from Seven Hills, suffered serious head wounds. He was treated at the scene by paramedics and taken to Westmead Hospital for treatment. He remains in a stable condition.
The younger man was arrested nearby and taken to Blacktown Police Station.
Crime scenes were established at both premises and investigators seized the hammer and other items for further forensic examination.
The man was charged with cause grievous bodily harm to person with intent and aggravated break and enter.
He has been refused bail to appear at Blacktown Local Court on Thursday.