A California-based consumer watchdog called, er... Consumer Watchdog is calling for a Department of Justice investigation into Google.

The group, supported by mobile entrepreneur Simon Buckingham and lawyers for two price comparison websites, praised the DOJ for its action against Google Books and the FTC probe into the acquisition of AdMob.

But Consumer Watchdog said Google was unfairly using its dominance in search to the detriment of both advertisers and users.

John M Simpson, consumer advocate at the group, said: “Google exerts monopoly power over Internet searches, controlling 70 percent of the U.S. market. For most Americans – indeed, for most people in the world – Google is the gateway to the Internet. How it tweaks its proprietary search algorithms can ensure a business’s success or doom it to failure.”

The watchdog accused Google of subsidising its other business with cash from its stranglehold on search.

The group suggested forcing Google to make its ad platform more transparent by making public the maximum bid for search terms, how many search terms are shown per page and how Google's "quality score" is calculated.

Simpson said such action could even include breaking Google into separate businesses or regulating it like a public utility.

Consumer Watchdog said it welcomed the ongoing investigation into Google Books by the DoJ, and the Federal Trade Commission's probe into the AdMob buy, but said it was: "past time to act against Google’s monopolistic and pervasive power over the entire Internet".

More details and the full letter to the DoJ are here. ®