Fifa vice-president Jim Boyce believes Manchester City should terminate the contract of Carlos Tevez after Roberto Mancini claimed the Argentina striker refused to come on as a substitute against Bayern Munich.
In a wide-ranging interview with Sky Sports News in Belfast, Boyce says world football's governing body could prevent Tevez from playing for a new club immediately, should City end his contract.
Tevez issued a statement on Wednesday morning and denied he had refused to play.
But Boyce told Sky Sports News: "If he has done what has been said, and it appears there is no doubt about it - no matter what has been said this morning - then I think his club would be better off with him not being part of it."
Asked directly if Tevez's contract should be terminated, Boyce responded: "Without a shadow of doubt. I don't think you can have someone at a club who has refused to go on the field of play, no matter who they are.
"If Manchester City Football Club prove it, write to Fifa and state the exact circumstances that happened last night then I believe Fifa should have the power, as they do for drugs-related cases and other cases, to ban the player from taking an active part in football.
"I would have no problem with that whatsoever. It hasn't occurred before but I think what happened last night was despicable."
Boyce, who is life president of the Irish Football Association, says Fifa could prevent him for immediately playing for another club, if City sacked him.
"If this player did what he has been accused of doing, then if Manchester City were to release him tonight I don't think it would be right if he could go and earn a considerable amount of money somewhere else next week," added Boyce.
"I would have no problems if some sanctions were imposed by Fifa in that respect. People within the clubs and within the top level of Fifa need to discuss this aspect of the game.
"If Carlos Tevez does it, who's to say someone else doing it the next week or the week after? It could become a massive problem."