The incident happened at 4.40pm on Sunday, August 28, when two men – including one armed with a machete - targeted Penny Petroleum Service Station, along the A1068.
They threatened the member of staff who was forced to hand over a quantity of money before they left the station and fled the area. The cashier was not injured during the robbery, but he was left incredibly shaken and distressed.
Detectives investigating the case have released an image of two men they would like to speak to in connection with the incident.
Detective Inspector Dave Harris said: “We are still carrying out a number of lines of inquiry to track down those responsible for this robbery.
“Several witnesses have been spoken to in relation to the case and CCTV is being constantly reviewed to identify those who carried out the robbery that day.
“We have released the image of two people who we would like to trace and anyone who knows who they might be should get in touch with police immediately.
“Even the smallest piece of information could help us piece together what happened and put those responsible before the courts.”
Anyone with information should contact Northumbria Police on 101 quoting reference 721 280816 or Crimestoppers anonymously on 0800 555 111.