Google is being investigated in Australia following claims it is using as much as $580m (£430m) worth of users' phone data a year to secretly track their movements.
A report published by Oracle claims the tech giant collects data from millions of Android users who are unwittingly paying for the privilege.
The report, which is part of a wider review on Google and Facebook's impact on advertising, claims that information on search history and location data is being passed directly from Android smartphones to Google and its parent company Alphabet.
Meanwhile the cost of transferring this data is being directly deducted from consumers' data plans operated by local service providers.
Oracle also claimed that Google can track Android devices in Australia without their location services being switched on.
Google said in a statement that it has its users' permission to collect data.
"Any charges for transmission of data over a cellular connection, including any location-related data, would be governed by a user’s mobile carrier plan,” it said.
“The types and quantity of such data that a user’s device transmits would depend on the products or services they use, and in some cases a user’s settings,” it added.
Australian watchdog the Australian Competition and Consumer Commission (ACCC) and the country's privacy commissioner said they were reviewing the report, specifically how much consumers really know about use of location data.
A spokeswoman for the regulator said: "The ACCC met with Oracle and is considering information it has provided about Google services."
She added: "We are exploring how much consumers know about the use of location data and are working closely with the Privacy Commissioner.”
The Australian investigation is the latest privacy concern around Google's operations and comes after Facebook suspended 200 apps as the investigation into its data misuse following the Cambridge Analytica scandal begins.