"We thought we would be announcing the new manager this afternoon and, as you all know, it was going to be Steve Bruce," said Latics chief executive Brenda Spencer.
"Unfortunately something has come up. It is an issue between Birmingham and Steve and, until it is resolved, we cannot announce him as our new manager.
"Our chairman (Dave Whelan) is desperate that we have a manager in place and he is hopeful that something will happen in the next 24 hours. I think we just have to sit tight, hold fire and hope that something will be resolved.
"We haven't signed a contract as yet, that was meant to be this morning.
"Like I say the issue has got to be resolved between Birmingham and Steve."