Detectives from Casey Crime Investigation Unit are investigating a series of burglaries which have occurred at business premises in Berwick, Cranbourne and Hallam.
Investigators believe that the same offenders are responsible for at least four incidents since 27 January.
On 27 January a man and a woman entered a pizza store on Hallam-Belgrave Road, Hallam around 2pm.
The couple made their way to the counter and stole cash from the register while staff were out the back.
The two then left the store.
On 15 February a man and woman entered a florist on High Street, Cranbourne around 2.50pm.
The couple again made their way to the counter and stole cash from the till.
Staff who were in the shop at the time were told to stay back during the incident.
Again the couple left the store and no person was injured.
Investigators believe that the same couple are also responsible for two thefts at a cake store on Adams Lane in Berwick.
These thefts occurred around 1pm on 24 February and 12.10pm on 1 March.
As with the other incidents, the couple have entered an unattended store and stolen cash from the till before leaving.
Police have released images of two people that they believe may be able to assist with their investigation.