A match-fixing investigation by Europol has hit the headlines this week, after the European police agency uncovered evidence of corruption and declared an investigation into nearly 700 matches since 2009.
Coleman, who had spells as manager of Spanish side Real Sociedad and Greek outfit Larissa, is not surprised by the revelations and states he witnessed incidents that aroused his suspicions while on the continent.
He told Sky Sports: "I've managed in Spain and I've managed in Greece and some of the games I've been involved in, I can tell you, weren't fair. Something was going on.
"You can't pinpoint it, you know there is something going on because some of the decisions that are made during the 90 minutes, or even some of the performances of the opposition, you are scratching your head. Bizarre things."
"I am looking at the statistics surrounding the corruption which is frightening, startling and shameful"
However, the former Fulham boss was keen to stress he has never noticed any corrupt activity while coaching in the United Kingdom.
He added: "I can honestly say with my hand on my heart, and I'm proud to say it, in all my experience of managing on our island I've never been suspicious of anything, never been suspicious of a referee being corrupt.
"I've never been suspicious of my own players, or the opposition players, or the opposition manager or anybody on my staff of being corrupt. I have never, ever, seen it, honestly.
"I am looking at the statistics surrounding the corruption which is frightening, startling and shameful. You are always going to get one or two who try and bend the rules but on that scale is alarming and disappointing."