City boss Roberto Mancini had earlier said a deal has been agreed for the Argentina who wants to leave Eastlands this summer as he is missing his young family, who are still in South America.
Brazilian side Corinthians are the only club to have made firm offers with an initial bid of £35million followed by an improved offer of £40million.
But Corinthians president Andres Sanchez has claimed that City "did not accept our proposal" and that the Premier League side had made further demands which were still under consideration.
And the club added: "For the moment there is nothing concrete on Tevez and the counter-proposal will be examined (by Sanchez) and the board."
According to Sanchez, City have asked Corinthians for "changes in the form of payment and the total value of the transaction".
The Brazilian club's president also suggested that the deal could not proceed until Tevez "settled an outstanding sum with the English club".