Heineken is facing a legal challenge from tequila-makers in Mexico who argue that its Desperado beer's claims that it contains tequila are false.

The Tequila Regulatory Council (CRT) is taking legal action against the Dutch firm which owns the brand.

"We cannot permit someone unscrupulously to affect tequila’s prestige ... Either they take the word tequila off it, or they put some tequila in," Ramón González, CRT director-general told The Financial Times.

He added that if the company does not respond to its warning the CRT will take legal action.

Defending the beer a Heineken spokesperson said that the beverage is, "a beer flavoured with tequila."

"The flavouring we use contains tequila, which we buy in Mexico from one of the members of the CRT," the company added.

Heineken stated that the drink complies with all labelling requirements.

It is unclear how tequila is used in the beer's brewing process, but the Madrid’s Public Health Laboratory has found that the final beer "does not contain tequila."

The drink is not on sale in Mexico. Heineken owns Cuauhtémoc Moctezuma, the country's second-largest brewery. Its products include Sol, Dos Equis, Tecate and Indio.