As he walked to his car parked underneath a unit block in Rosehill, a man was cut with a knife and then threatened with a home-made hand gun.
Police said the 44-year-old was approached by another man in the car park about 10.40pm on Wednesday. He was threatened with a knife and was cut on his right index finger.
The armed man then chased the 44-year-old and demanded money.
When the 44-year-old attempted to call police on his mobile phone, the other man got into the passenger-side of a car and allegedly threatened him with a home-made handgun.
Police said the offender and driver then left.
The 44-year-old attended Granville Police Station to report the incident.
The alleged offender is described as being of Caucasian appearance, 35-40 years-old and medium build.