Germany's antitrust regulator on Tuesday said it has opened an investigation into Google over anti-competitive practices, wielding a new law that has already been used to scrutinize other U.S. tech giants. 

The Federal Cartel Office will investigate European units of Google in Germany and Ireland, as well as its parent company, Alphabet, in California, it said in a statement.  

The investigation has an "outstanding cross-market significance" due to the breadth of Google's digital products, Cartel office head Andreas Mundt said.  

"Google's business model is very fundamentally built on the processing of its users' data," Mundt said. "Google has a strategic advantage here due to its established access to competitively relevant data." 

A key question in the probe was whether consumers "have sufficient choice over the use of their data by Google if they want to use Google services," he said. 

Google said people use its services because they are helpful, not because they are forced to do so or because they cannot find any alternatives. 

"We give people easy control over how their information is used, and we limit the use of personal information," spokesman Ralf Bremer said, adding that Google would assist the cartel office with its inquiries.

The investigation follows the application of a new law giving the authorities more power to rein in big tech companies, with proceedings similar to those recently launched against Amazon and Facebook. 

Under the amendment to Germany's competition law passed in January, the watchdog said it now has more power to "intervene earlier and more effectively" against big tech companies, rather than simply punishing them for abuses of their dominant market position. 

Last week, the Federal Cartel Office said it was examining whether Amazon has "an almost unchallengeable position of economic power," having already launched two traditional abuse control proceedings. 

The watchdog has also employed its new powers to widen the scope of an investigation into Facebook over its integration of virtual reality headsets. 

The push to tighten legislation comes as big tech companies face increasing scrutiny in countries around the globe, including in the U.S., where Google and Facebook are facing antitrust suits.

(With input from agencies)