Cash was stolen in a robbery of the McColl's store in Severn Beach.
A man and a woman entered the Beach Road convenience shop, wearing balaclavas, at about 6am on Friday (April 9).
An Avon and Somerset police spokeswoman said: "One threatened shop staff with a screwdriver before taking cash from the tills. Thankfully no one was hurt in the incident.
"Officers have carried out house-to-house and other enquiries since the incident and continue to appeal for anyone with information which could help the investigation to come forward."
She added police are following up "positive lines of enquiry".
"If you have any dashcam, smart doorbell or other footage which could help, or if you saw someone discarding any items or behaving suspiciously in nearby streets, call 101 quoting reference 5221075439," the force spokeswoman continued.
To get breaking news like this straight to your inbox, click here
"Alternatively ring the independent charity Crimestoppers on 0800 555 111.
"They never tell the police who you are, just what you know."
