DUBLIN (Reuters) - Ireland's Data Protection Commissioner (DPC) opened an EU-wide probe on Friday into whether Ryanair's use of facial recognition technology to verify the identity of customers booking through third party websites violates the bloc's privacy laws.

The regulator said it had received a number of complaints from Ryanair customers across the European Union over the airline's practice of requesting additional verification from those booking travel tickets from third party sites or online travel agents, as opposed to directly with Ryanair.

The Irish carrier, Europe's largest by passenger numbers, says on its website that in order to comply with safety and security requirements it must verify the identity of passengers' booking elsewhere because agents often do not provide Ryanair with customers' contact and payment details.

Passengers can avoid verifying through facial recognition by showing up at the airport at least two hours before departure or submitting a form and picture of their passport or national ID card in advance, a process Ryanair said can take seven days to complete.

A similar process is not required when booking through Ryanair's website or mobile phone app.

Ryanair said last year when a complaint was lodged on the issue that its biometric and non-biometric processes were both fully compliant with all the EU's General Data Protection Regulation (GDPR).

(Reporting by Padraic Halpin; Editing by Mark Potter)