Marsh has revealed to talkSPORT that his source at City has claimed that Toure will cut ties with the Premier League champions if his current £220,000-a-week salary is not increased.
"[My source] has never let me down," Marsh told the radio station. "He has always been right. The conversation we had [on Tuesday] was if City don't come through with a massive increase in wages, then Yaya Toure will be off."
The 31-year-old, who has claimed that he will clarify his future after the World Cup, signed a new four-year deal just last year.