The man, who stole cash from Ampol service station in Albert St, Redan, about 8.30pm Tuesday, has been linked to a burglary on Sunday.

A man fitting the same description was caught on camera using a jemmy bar to break into the back door of Petstock in Latrobe St, Sebastopol, about 9pm Sunday.

Ballarat CIU Detective Senior Constable Dave McLennan said cash was stolen in both robberies.

"We would certainly like to track him down so he doesn't do it again," Det Sen Const McLennan said.

"He's obviously a very desperate person who will most probably commit further crimes of this nature."

Police have released security footage of the earlier burglary in the hope someone will recognise the offender.

He is shown wearing the same clothes as Tuesday night's attack.

"I believe it's the same offender," Det Sen Const McLennan said.

"It's exactly the same top, the same clothing.

"Presumably he's been wearing the same clothes ever since."

The suspect is believed to be aged in his 20s. He is of thin build, and was wearing black jeans, runners, a red and white top with a red hood.

He was wearing a balaclava or beanie and carrying a black backpack during Tuesday night's hold-up.

Footage of Tuesday's armed robbery showed the suspect waving the hammer around violently.

At one staged the suspect smashed the counter.

Police have urged the victim of Tuesday night's attack to seek counselling. He was unharmed but shaken by the ordeal.

"The complainant is very distressed, naturally enough," Det Sen Const McLennan said.

He said police were following avenues of inquiry but wanted the public's help identifying the man.

He said the red and white top was "distinctive" and the suspect had probably worn the same clothes for three days.

The suspect was last seen running north along Albert St toward the centre of Ballarat about 9pm Tuesday.

"He may have had a car or he may have lived nearby," Det Sen Const McLennan said.

"This person may have been seen at a hotel or a fast food store in Sebastopol.

"There are numerous people who may have seen him."

Police have not disclosed the amount of money stolen in the robberies.

People with information are asked to contact Ballarat CIU on 5336 6080 or Crime Stoppers toll-free on 1800 333 000.