The actress, 43, best known for her role as Michelle Connor on the Weatherfield cobbles, will front an investigative consumer series for BBC One.
Alongside reporter Ashley John-Baptiste, she will "explore a rapidly growing and particular type of scam - the so called 'romance frauds' that every day sees unsuspecting online daters conned out of tens of thousands of pounds".
Each episode of the new series "will see Kym and Ashley look into one case, in the forensic style of a crime investigation," the BBC said.
"Their aim is to expose the sophisticated techniques fraudsters use to pull at an individual's heartstrings, so they can empty their bank balance.
"They will find out how the criminals manage to appear so convincing, identify the real owners of the photos they've used to trick people into trusting them, unpick the other evidence they've supplied, and sometimes even make contact with the crooks themselves."
The week-long series, For Love Or Money, will air on BBC Daytime.
Other programmes announced include Night Force, to "shine a light on those working through the night" and Call That Hard Work, in which people swap jobs.
Acting head of BBC Daytime and early peak Carla-Maria Lawson said: "I believe these new formats will enhance our offering to viewers of shows that give a fresh take on relevant issues."
Marsh is leaving her Corrie role later this year.