The comments underline growing regulatory concerns across Europe about the collection of personal data by tech companies.

Last month, the Federal Cartel Office kicked off a sector inquiry into online advertising after advertisers and publishers voiced worries about Google (>> Alphabet) and Facebook strong market position.

The move came two months after it launched a sector inquiry to find out how smart TV makers handled user data and the terms of their contracts. Smart TVs, which allow viewers to receive and transmit their user data, have become increasingly popular.

"There will be a third one (sector inquiry) in a short period of time which we are hoping to get out," antitrust chief Andreas Mundt told a conference organised by the Studienvereinigung Kartellrecht association.

Asked by reporters about the investigation's focus, he said: "If there are deficits (gaps in enforcement), it will be digital markets."

Granted new powers in June, the German watchdog can launch wide-ranging investigations if it has reasonable suspicion that consumer law provisions have been violated but it cannot sanction infringers or open individual cases.

(Reporting by Foo Yun Chee; Editing by Edmund Blair)

By Foo Yun Chee

Stocks treated in this article : Facebook, Alphabet