At around 3:15am on Sunday morning police were called to the Alpha Street carpark in Sydney's inner west. Officers from Blacktown Police Area Command attended the scene to find a man with stab wounds.
The local man was treated by paramedics at the scene before being taken to Westmead hospital, while another man was arrested and is currently assisting police with their investigation.
The victims current condition is unknown.
Anyone with information related to this incident should call Crime Stoppers on 1800 333 000.