According to media reports on Monday, Blues had tabled an estimated £8million offer for the 23-year-old French winger.
However, N'Zogbia's agent, Franck Peslerbe, has revealed that the Latics have rejected the reported bid.
"Birmingham have made a bid for Charles and Wigan have turned it down," Peslerbe told skysports.com.
"There are also some other English sides apart from Birmingham interested in Charles.
"Charles is currently away on holidays but I am in discussions with Wigan.
"Everything depends on Wigan and if they accept a bid then things can go forward.
"If it was a good solution for Wigan and a good project for Charles then something might happen
"Wigan have a figure they expect for Charles and we will see if anyone meets that."