Police investigating the armed robbery of a service station at Waterford West on Wednesday morning have released CCTV images of the incident.

Investigators believe the incident may be linked with a similar armed robbery at a Park Ridge service station on June 9.

In both instances, two women were seen entering the businesses, allowing the automatic doors to open before the armed robberies take place.

At 11.30pm on June 9 one man was armed with a screwdriver when he stole cash from the Chambers Flat Road service station at Park Ridge.

Around 2.50am on June 19 two men robbed a Kingston Road business, threatening a male staff member with a knife before stealing cash and fleeing the scene.

Both men are described as being Caucasian in appearance, aged in their early 20s with one man being about 175cm tall while the other is about 165 to 170cm tall.