The US state attorneys general investigating Alphabet Inc's Google for potential antitrust violations are leaning towards pushing for a breakup of its ad technology business as part of an expected suit, CNBC reported on Friday.

The Justice Department and nearly all state attorneys general have opened investigations into allegations that Google has broken antitrust laws. The federal probe focuses on search bias, advertising and management of Google's Android operating system. Google's shares were up 1.6 per cent on the day.

"We don't have any updates or comments on speculation. The facts are clear: Our digital advertising products compete across a crowded industry with hundreds of rivals and technologies, and have helped lower costs for advertisers and consumers," Tarallo said.

Reuters and others reported in mid-May that state attorneys general led by Texas were likely to file an antitrust lawsuit against Google later this year. The Justice Department is also moving toward bringing a case as soon as this summer, The Wall Street Journal reported then.

Google on Thursday announced several leadership changes, including expanding senior vice president Prabhakar Raghavan's oversight to search engineering in addition to development of the company's ads systems. Several antitrust complaints against Google center on the company's promotion of its own services in the search engine, and how it charges for search ads. In his expanded role, Raghavan can control the entire canvas of Google's search engine, including organic results and ads.

Google, Facebook Inc, Amazon.com Inc and Apple Inc are under a series of probes into allegations that the tech behemoths use their clout to unfairly defend their market share. The federal probe of Google focuses on search, advertising and management of its Android operating system.

On Android devices, Google search had been the default for years. However, a fine imposed by the European Union in 2018 led Google to offer other search options to users. According to a report in The Wall Street Journal last month, the Justice Department is aiming to bring a case against Google as early as this summer.