Melbourne Embona Armed Robbery Taskforce detectives are investigating a number of attempted armed robberies in Docklands on 31 December, Victoria Police say.
Investigators have been told a man entered a bottle shop on Rakaia Way about 1.30pm brandishing a knife and demanding cash.
He was chased out of the store empty-handed by two staff members, one also armed with a weapon.
Shortly after, about 2pm, the same man entered a convenience store on Docklands Drive.
It is believed the man, who may have been in the company of a female on this occasion, followed a staff member behind the counter before producing the knife and demanding cash from the register.
The staff member asked the female for help, but she did not assist.
The man attempted to open the register himself but was unsuccessful.
Later that day, about 7.10pm, investigators believe the same man approached a fast food store on Star Circus.
He presented a white plastic bag to the store attendant and demanded cash be placed in there, before again leaving empty-handed.
At 10.20pm, the same man then entered a gaming venue on Star Crescent and approached the counter.
He showed the attendant the plastic bag and demanded money, before fleeing empty-handed.
The man has been described as Caucasian and aged in his 20s with a skinny build and a small amount of facial hair on his bottom lip.
He was wearing a black cap, grey hoodie, dark shorts with a red and white stripe and black runners in the first incident.
During the next three incidents, he was wearing the same shorts with a black Adidas jumper with white stripes down the arm and white runners.
Police have released images and CCTV footage of a man they believe may be able to assist with their enquiries.
Anyone with information is urged to contact Crime Stoppers.
