According to the organisation, several cases remain unresolved and could ultimately result in sanctions of more than one million euros if serious breaches are confirmed.

AUC said there was a high likelihood of sanctions because around 90 per cent of complaints that have already been resolved found some form of regulatory infringement. Most involved alleged hidden advertising, where promotional content failed to clearly disclose a commercial relationship with a brand.

The report said many posts used terms such as "ads", "ambassadors" or "paid collaborations" to indicate promotional content. However, the National Commission for Markets and Competition (CNMC) has argued that such wording is not always sufficient to identify advertising clearly.

The regulator maintains that the word "advertising" should be displayed prominently and unambiguously to avoid misleading consumers.

Several cases still awaiting decisions

The report includes examples of cases that were upheld, cases resolved through commitments to cease the conduct and a number that are still pending. Among those awaiting final decisions are cases involving Banderas, Putellas and Roca.

AUC said that, depending on the outcome, both the individuals involved and the brands concerned could face penalties of up to one million euros for very serious infringements under Article 160 of Spain's General Audiovisual Communication Law.

Under current legislation, fines for very serious offences range from 60,000 euros to 1.5 million euros, depending on factors including the content creator's declared annual income. Serious offences can attract penalties of between 30,000 euros and 750,000 euros, while minor infringements carry fines ranging from 10,000 euros to 150,000 euros.

The report also warned that companies themselves could face penalties of up to 10 per cent of their global turnover. It noted that the CNMC has urged businesses working with influencers to ensure promotional agreements comply with existing regulations.

However, the report stressed that the inclusion of Banderas, Putellas and Roca in pending cases does not mean they will necessarily be sanctioned. Their cases remain on hold while decisions are made on whether the content will be removed, amended or left unchanged.

Earlier this year, Kira Miró, Oriana Marzoli, Edurne, Blanca Romero, Putellas, Lola Lolita, Jessica Bueno and Bustamante were also named in cases involving alleged hidden advertising practices.

At the time, AUC president Alejandro Perales told Telecinco: "The vast majority of offenders are guilty of misleading advertising. They're recommending products without making it clear that it's advertising."