Armed Crime Squad detectives are appealing for public assistance to solve an armed robbery at the Green Gully Soccer Club in Kealba on 13 June.

Investigators have been told a lone man entered the venue in Club House Place around 11.30pm armed with a long arm firearm and made a demand for money from a staff member.

The staff member, who was at the TAB counter, ran into a rear office, leaving the man at the counter.

The man grabbed a quantity of cash from the counter and left the venue and was last seen running in a westerly direction.

Police believe he ran through nearby parkland and into Ardena Court or Tarella Drive where he may have had a vehicle parked.

The man is described as being heavyset and was wearing dark clothing, including a black jumper with the hood over his head and a black and white bandana over his face.

Detectives have released images of the man.