The incident took place on Saturday 14 May at just before 7.30pm a man entered a petrol station shop on Hoddesdon High Street and demanded staff hand over money, this was refused and the man fled.
Then at around 17.40pm a man entered the Post Office, High Road, Broxbourne and staff were told to hand over money and again this was denied before the man made off.
In both instances, the man was holding a bag in which he suggested he had a weapon. However, no weapon was seen in either incident.
Detective Inspector Chris Ross, who is investigating, said: “These were two distressing incidents for the members of staff involved and we have released the image of a man we would like to speak with.
“He was in the area at the time and could assist with our enquiries.
“If you recognise him, witnessed with incidents or have further information please get in touch.”
Anyone with information is asked to please email email@example.com
You can also report information by quoting reference 41/38147/22 or 41/38149/22 by calling 101 or Crimestoppers anonymously on 0800 555 111 or visiting crimestoppers-uk.org.