MADRID (Reuters) -Spain's High Court on Monday upheld a temporary ban on Worldcoin's iris-scanning venture, in the latest blow to a project that has sparked privacy concerns in several countries.

The court said the "safeguarding of the public interest" must prevail, dismissing an appeal by Worldcoin's owners.

Co-founded by OpenAI CEO Sam Altman in 2019, Worldcoin aims to create a global identity system by getting people to have their irises scanned in exchange for free cryptocurrency and a digital ID.

The venture was temporarily banned on Wednesday by Spain's privacy watchdog following complaints of insufficient information, the collection of data from minors and not allowing the withdrawal of consent.

The watchdog said the processing of biometric data, which has special protection under the European Union's General Data Protection Regulation, "entails high risks for people's rights, taking into account their sensitive nature".

It told Worldcoin to stop collecting personal information and stop using data it had already gathered.

Worldcoin said in a statement on its website that Spain's regulator had circumvented the "accepted EU process and rules" without giving details.

More than four million people in 120 countries have signed up to have their irises scanned by Worldcoin, according to its website and queues of people eager to sign up to try out the new tool have formed in Spanish metro stations in recent weeks.

But the project has drawn criticism from privacy campaigners from Argentina to Germany over the collection, storage and use of personal data.

Spain's High Court said that in the event of an eventual favourable judgment lifting the ban, the company would be compensated for any lost income, thereby rejecting the argument of "irreparable damage" alleged by the appellant.