A statutory inquiry has been launched into Google Ireland's processing of personal data.
The Data Protection Commission says its investigation is in relation to the internet giants online Ad Exchange.
Google describes the service as "real-time marketplace... for buying and selling advertising".
The commission says its looking to establish whether processing of personal data carried out at each stage of an advertising transaction is GDPR-compliant.
Google's data-retention practices will also be examined.
In a statement, the Commission said the inquiry has arisen from an ongoing examination of data protection compliance.
Data Protection Commission opens statutory inquiry into Google Ireland Limited https://t.co/aWrC0bzZ3s pic.twitter.com/BWh005X1uT
— Data Protection Commission Ireland (@DPCIreland) May 22, 2019
The Commission has opened a number of investigations into tech companies operating in Ireland.
Last month, they launched a statutory inquiry into Facebook after it emerged the social network stored passwords in unencrypted format.
If a company is found in breach of GDPR rules by a statutory inquiry, the Data Protection Commission has 'corrective powers' such as issuing fines or a "temporary or definitive ban on processing or a suspension of international data transfers".
