A number of Spanish media outlets have been critical of the Welshman's fitness, with several reports earlier this week even suggesting Bale could face months on the sidelines, with conflicting stories claiming he had either a hernia or slipped disk.
Madrid quickly dismissed suggestions that the 24-year-old has a serious back problem, though, and Perez has now hit out at the press for the way they have reported on the €100 million man in recent weeks.
"Certain media outlets surpass what criticism is. It's a permanent campaign. The information published about Bale is extremely cruel, even if it was true. Being false, it becomes clear that they have a target," Perez told Punto Pelota.
"Should Bale have a slipped disk, we would have told the media so. We would never have signed him if that was the case.
"Here in Madrid, you know the press try not to appear as Madridistas. News like the report about Bale would never have been published in Barcelona, being false as it is.
"There's a campaign against myself and others at Madrid."
Bale has made three official appearances for Madrid since his move from Tottenham Hotspur.