Police investigate the scene of the Springvale convenience store armed robbery, in which a man was shot in the arm. Photo: David Crosling

It is believed a man, armed with a firearm, entered a convenience store on Springvale Road shortly before 4.30am.

The offender, who had followed a male customer into the store, approached the front counter and made demands for cash.

A male staff member attempted to lock himself in a store room behind the counter when the offender discharged his firearm.

The store attendant, a 40-year-old, sustained a gunshot wound to his arm during the incident and was conveyed to hospital with non-life threatening injuries.

The witness was uninjured.

The male offender tried to access the till but was unsuccessful and fled the scene on foot in a southerly direction.

He is described as about 180cm tall and was wearing a beanie, black and white bandana, dark-coloured top and dark-coloured pants.

Police are investigating connections to an attempted armed robbery that occurred a short time earlier at a near-by service station on Heatherton Road.

It is understood an unknown male, armed with a firearm, attended the store near Hosken Street and made demands for money.

This robbery was also unsuccessful and the offender fled the scene on foot empty-handed.

In this instance the offender described was wearing a grey hooded jumper, dark-coloured tracksuit pants and a bandana across face.

Armed Crime Squad detectives are investigating the circumstances surrounding both incidents.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au.