Bale would listen to Real offer
Barnett was speaking on the Futboleros show on MarcaTV on Tuesday, and he was asked about the future of the Welsh star - who has been heavily linked with Madrid in recent days.
"If Florentino [Perez, Real president] is interested in Gareth Bale, then that would be an honour and we would listen, but his contract is with Tottenham," he said.
"But we are not free to talk to anyone."
Barnett also dismissed reports that Bale was on the verge of signing a new long-term deal with Tottenham.
"No, we have not talked to anybody," he said when asked a about a possible new deal. "I do not know if there has already been an offer. What I know is that the player has three years left on his contract."
Barnett did insist, however, that Bale is worth more than Brazilian superstar Neymar - who has just agreed a move to Barcelona, shunning the interest of Real.
"He is a much better player than Neymar, he has proven himself in one of the best leagues in the world, the Premier League," he said. "And I would hope any club wanting him, would not want him because they lost out on Neymar but because he was first choice.
"This is all crazy, but whatever Neymar cost - Gareth Bale is worth more."