Internet search engine DuckDuckGo alleges that Google hurts its growth prospects which is currently investigated by the US Federal Trade Commission (FTC) on allegations of breaking antitrust laws.
FTC commissioners are planning to file a complaint against Google if they find enough evidence that the company manipulated search results.
DuckDuckGo was started by Gabriel Weinberg, a Massachusetts Institute of Technology graduate, five years ago.
Weinberg told Reuters that it is difficult to make his DuckDuckGo the default search site in Google's Chrome web browser, and that Google disadvantages his company in the Android mobile operating system as well.
According to Reuters, there have also been complaints about Google blocking access by rivals to its Android wireless phone operating system and about inappropriately asking for injunctions for infringing on standard essential patents, which ensure interoperability.
Weinberg, who met with the FTC recently, said that the Android wireless phone comes with Google as the phone's standard search mechanism.
DuckDuckGo can be added as an app to a mobile device, which is less convenient than being the default search engine, said Weinberg.
He also said his company had tried to buy the duck.com domain from its previous owner, On2 Technologies, but was rejected.
Google acquired the domain when it bought the entire firm, and redirects duck.com traffic to Google.com.
"It only started redirecting after we inquired about (buying the domain name)," said Weinberg. "It causes confusion."
A Google spokeswoman told Reuters that the company acquired On2 in 2010 and then pointed duck.com to Google's homepage, "just as we have for many domains we've gotten through acquisitions."
Weinberg told Reuters that Google's Chrome browser also made it difficult to change the instant search feature at the top of the browser to DuckDuckGo. "It's one-click to get onto Firefox and it's five steps on Chrome and people generally fail," he said.
The Google spokeswoman said popular search alternatives were offered on its Chrome browser in a dropdown menu, such as Yahoo and Microsoft's Bing, but any search engine could be easily added.