Melbourne store hit by same thief 3 times

A persistent thief has targeted the same Melbourne service station three times since Thursday.

The first robbery occurred about 3.30pm on Thursday, and the man returned about 11.20pm on Friday and again on Sunday about 6.30am.

"The man has made verbal threats to staff and in one instance claimed to have a firearm but no firearm was sighted," according to Victoria Police.

The man snatched a small amount of cash during one of the robberies.

Police have released a security camera image of caucasian man in his early 20s and who made no attempt to mask his identity.

The service station is in South Melbourne, on the corner of City Road and York Streets.