Google is facing another antitrust lawsuit as attorneys general from 38 US states file a complaint about the tech giant's search monopoly.

In the lawsuit, the US states allege that Google "willfully maintained, abused, and extended" its search engine monopoly power by squeezing out rivals through mechanisms like exclusionary distribution agreements with mobile device manufacturers and by maintaing strict control over its Search Advertising 360 (SA360) tool.

The US Justice Department and 11 states filed a similar lawsuit against Google in October which focused on the company's exclusionary agreements that have seen Google pay the likes of Apple to become its default search engine.

This new lawsuit sees states expand on previously outlined behaviour in order to "[demonstrate] a broader pattern of Google's anticompetitive conduct".

One of the new arguments relates to SA360 – a tool used by to place ads on search results across different search platforms, including Microsoft Bing.

The states argue that Google sold SA360 to advertisers under the guise that it would be platform neutral but in reality the tech company used its tool to direct marketers away from competitors like Bing and toward Google Search.

They also allege that Google deliberately maintains a dependence on Search for other verticals such as travel and hospitality which rely on Search to reach customers.

Colorado Attorney General Phil Weiser, who is leading the coalition, said Google's domination of the search engine market was severly limiting people's choices.

"Google’s anticompetitive actions have protected its general search monopolies and excluded rivals, depriving consumers of the benefits of competitive choices, forestalling innovation, and undermining new entry or expansion,” Weiser said in a statement.

“This lawsuit seeks to restore competition.”

As far as relief goes, the attorneys general are seeking a court's recognition that Google has contravened antitrust laws and have not ruled out "structural divestitures" in the same vein as a recent filing against Facebook which seeks to rid the social media giant of Whatsapp and Instagram.

Google naturally defended itself against the lawsuit's allegations in a blog post by Director of Economy Policy, Adam Cohen.

Cohen argues that the design and business decisions criticised in the court filing have always been about improving Search, not making lots of money out of selling advertisements.

"When you search for local products and services, we show information that helps you connect with businesses directly and helps them reach more customers," he said.

"This lawsuit demands changes to the design of Google Search, requiring us to prominently feature online middlemen in place of direct connections to businesses.

"Redesigning Google Search this way would harm the quality of your search results."

Google made a similar argument upon the release of the Australian government's news media bargaining code which aims to see Google pay news organisations for stories that appear in search results.

At the time, Google Australia Managing Director Mel Silva warned users that the regulation would mean one of the most powerful countries in the world "could no longer guarantee" that searches would yield "relevant" or "helpful" results.