Investigators have been told a man, aged in his 50s, entered the Subway store in Sebastopol and approached a staff member behind the counter about 10.50am.

He produced a knife and demanded cash, which the staff member handed over.

The man was last seen leaving the store on foot and crossing Albert Street.

Ballarat Crime Investigation Unit detectives have been investigating the incident and on Wednesday released images of a man they believe may be able to assist their investigation.

The man is perceived to be Caucasian, about 175-185cm tall, with a medium build and tattoos on both forearms.

He was wearing a blue basketball cap, blue surgical mask, a dark shirt, tan shorts, blue socks and dark shoes at the time of the incident.

No one was physically injured during the incident.

Anyone who recognises the man or has information is urged to contact Crime Stoppers on 1800 333 000 or at www.crimestoppersvic.com.au.

Earlier, Tuesday:

Police are searching for an armed man who demanded money from a staff member at a Sebastopol fast food outlet on Tuesday morning.

A man armed with a knife walked into the Albert Street Subway store about 10.50am, police said.

It is understood the man made demands before he fled on foot with an amount of cash.

Nobody was injured during the incident.

Police quickly flooded the area and spoke with witnesses.

No arrests have been made as of Tuesday afternoon.

Ballarat detectives told The Courier they were continuing to investigate what had occurred.

Detectives appealed for anyone with information, CCTV or dashcam footage around the time of the incident to contact Crime Stoppers on 1800 333 000.

A report can also be filed online at www.crimestoppersvic.com.au.

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