The US Department of Justice on Tuesday said it would demand that Google make profound changes to how it does business and even consider the possibility of a breakup, after the tech juggernaut was found to be running an illegal monopoly.

Determining how to address Google's wrongs is the next stage of a landmark antitrust trial that saw the company in August judged a monopolist by US District Court Judge Amit Mehta.

An order to break up Google or require deep changes on how it does business marks a profound change by the US government's competition enforcers that have largely left tech giants alone since failing to break up Microsoft two decades ago.

Google dismissed the idea as "radical."

The government told the judge in a court filing that it was considering options that included "structural" changes which could see them asking for a divestment of its smartphone Android operating system or its Chrome browser.

The Department of Justice also said it could ask for the prohibition of Google's default agreements with third parties that sees it pay tens of billions of dollars every year to Apple.

Requiring Google to make its search data available to rivals was also on the table, it said.

This case, focusing on Google's search engine dominance, is part of a broader legal offensive against the company's alleged antitrust violations in the US.

Google faces additional challenges from the DOJ regarding its advertising technology and recently lost a jury trial to Fortnite-maker Epic Games over its Google Play store practices.

The DOJ's remedy proposals are part of a "high-level framework" outlining how it envisions implementing the court's verdict.

A more detailed request will be submitted in November, followed by arguments from both sides in a special hearing scheduled for April.

Google, in a blog post, criticized the government's proposed remedies as "radical" and expressed concern that the DOJ's requests "go far beyond the specific legal issues in this case."

Regardless of Judge Mehta's eventual decision, Google is expected to appeal, potentially prolonging the process for years and possibly reaching the US Supreme Court.

The trial, which concluded last year, scrutinized Google's confidential agreements with smartphone manufacturers, including Apple.

These deals involve substantial payments to secure Google's search engine as the default option on browsers, iPhones, and other devices.

The judge determined that this arrangement provided Google with unparalleled access to user data, enabling it to develop its search engine into a globally dominant platform.

From this position, Google expanded its tech empire to include the Chrome browser, Maps, and the Android smartphone operating system.

According to the judgment, Google controlled 90 percent of the US online search market in 2020, with an even higher 95 percent share on mobile devices.