Rovers keeper Brad Friedel was seen to hand referee Graham Barber an object that had been thrown onto the field of play immediately after Lucas Neill scored Rovers second goal at St. Andrew's.
The club have issued a statement on the incident through their official website, www.bcfc.com in which they promise to ban for life the offender if identified.
The statement reads: “Birmingham City Football Club does not and will not tolerate the throwing of coins or any other objects by spectators at St Andrews.
“Reports that a coin was thrown onto the pitch at Saturday’s game are being treated extremely seriously by the club.
“Furthermore the club believes that behaviour of that sort has no place in football. But, contrary to some newspaper reports which alleged that multiple coins were thrown on to the pitch, the club understands that it was in fact a single object.
“A single coin was found on the ground and thankfully no-one was hurt. The club is co-operating fully with the FA in its investigations and is currently examining CCTV footage from Saturday’s match.
“Any evidence which is obtained from the CCTV and witness statements will be passed to West Midlands Police and in addition the culprit will be banned from St Andrews for life.
“Whilst the club believes this is an isolated incident, they will be stepping up their CCTV monitoring of the crowd to ensure there is no repeat of this unacceptable behaviour.”