Police have released CCTV images as they continue to investigate an attempted armed robbery in Marrickville last month.

About 6.15pm on Sunday 28 May 2017, a man entered a supermarket on Illawarra Road and threatened an employee with a knife.

The man left the store and was last seen riding a red mountain bike south on Illawarra Road.

Police from Marrickville Local Area Command are investigating the incident and have released CCTV images of a man who may be able to assist with their inquiries.

He is described as being in his late 40s or 50s and Caucasian in appearance. He is between 170-175cm and has a thin build. He may have a tattoo on the back of his left hand. In the CCTV images the man is seen wearing a black hooded jacket with a small white symbol on the back, dark grey pants, white runners, black sunglasses and an orange and black helmet.