Around 1.20am a 27-year-old woman was working within the BP service station on Glasgow Road when a man came in brandishing a knife and demanded money.
The would-be thief ran off when the woman raised the alarm.
The suspect is described as white, 5’7” tall, of slim build and aged between 20-30 years.
He was wearing a blue jacket with the hood up and dark-coloured trousers.
Detective Constable Victoria Ross, Wishaw CID, said: “Although nobody was injured, this was a terrifying ordeal for the woman who was simply at her work.
“Officers have been checking CCTV and know that the man was outside the service station for a while before he entered and we are appealing to anyone who may have seen him.
“There were a number of cars and people walking by at the time who may have information that can help.
“We urge you to come forward.”
Anyone with information about this incident should contact Police via 101, quoting incident number 0254 of Monday 23 July 2018.
Alternatively you can contact Crimestoppers on 0800 555 111 where information can be given anonymously.