Police are investigating following two armed robberies in Chelsea Heights and Carrum Downs this morning.

It is believed two men wearing balaclavas attended a service station on Wells Road, Chelsea Heights about 4am and smashed the front door with what is believed to be a crow bar.

The offenders demanded a staff member open the door and he complied.

The pair stole cigarettes and cash before fleeing.

It is believed a taxi driver startled the pair before they continued to leave the area in what is believed to be a stolen silver Holden Commodore sedan with Victorian registration YGW810.

It is believed the car was being driven by a third unknown person and was last seen travelling towards the freeway.

No one was injured during the incident.

It is believed the same offenders may have been involved in an armed robbery at a fast food restaurant on Hall Road in Carrum Downs about 4.50am.

During the second armed robbery, the offenders armed themselves with what is believed to be a tyre lever and approached a staff member, striking him to the head.

The offenders stole cash from numerous registers in the store and fled.

Investigators have released images and CCTV of two men they believe may be able to assist with their enquiries.