Senator Herb Kohl (D-Wis.), chairman of the anitrust subcommittee, said he will put special focus on Google in the current session, examining its bid to expand through acquisitions and search industry practices.

In a release, Kohl said that as the world’s largest search engine, with about 60 percent of the market, e-commerce sites that compete with Google say they are being unfairly treated in search ranking.

Google declined to comment on the lawmaker’s announcement.

“In recent years, the dominance over Internet search of the world’s largest search engine, Google, has increased and Google has increasingly sought to acquire e-commerce sites in myriad businesses,” Kohl said in a release outlining his agenda for the congressional session. “In this regard, we will closely examine allegations raised by e-commerce websites that compete with Google that they are being treated unfairly in search ranking, and in their ability to purchase search advertising.”

Google’s proposed acquisition of online travel service ITA has garnered criticism by competitors such as Expedia, who say the merged firm would have too much influence over Internet flight and other travel search.

Stifel Nicolaus analyst Rebecca Arbogast wrote in a recent note that the deal, under review at the Justice Department, will likely be approved but with conditions that provide some expanded access to ITA travel data.

“But we recognize there are complicating factors that could still play out so that DOJ moves to block the deal,”Arbogast wrote. “A fundamental question is whether Google must acquire ITA in order to innovate in travel search, or whether it can innovate by licensing the ITA data.”

Google’s Matthew Cutts, a leading engineer for search, traveled to the District last January to meet with lawmakers and media to argue against a growing call from competitors and some consumer groups for federal regulation over search.

European regulators have launched an investigation brought by complaints from some companies that Google has purposefully lowered their rankings, making it difficult to compete. The New York Times reports on E.U. queries to advertisers as it investigates those claims.