Zidane revealed Madrid are working on selling Bale after omitting the four-time Champions League winner from the squad that lost to Bayern Munich in the International Champions Cup on Saturday.
"We hope he leaves soon, it would be best for everyone," Madrid's head coach said.
The comments have not gone down well with the Bale camp.
"Zidane is a disgrace to speak like that about someone who has done so much for Real," Bale's agent, Jonathan Barnett, told ESPN.
"If and when Gareth goes it will be because it is in the best interest of Gareth and nothing to do with Zidane pushing."
Barnett this week dismissed the latter link as "rubbish" amid doubts over Spurs' ability to compete financially.
Few clubs in Europe appear capable of meeting Madrid's asking price and Bale's likely wage demands, complicating LaLiga side Madrid's hopes of negotiating his exit.
However, Zidane said: "We are working on his transfer to a new team."