Google has complained to both the European Commission and the US Justice Department about the next version of Internet Explorer, saying it unfairly funnels users to Microsoft's MSN search engine.
Internet Explorer 7, which will be included in the much-delayed Windows Vista operating system, includes a search box in the top right corner that by default sends users to MSN Search.
Google told The New York Times that it has expressed concerns to the EC and Justice Department about how this bundling will affect competition in the Web search business.
"The market favours open choice for search, and companies should compete for users based on the quality of their search services," Marissa Mayer, vice-president for search products at Google, reportedly said. "We don't think it's right for Microsoft to just set the default to MSN. We believe users should choose."
Google did not respond to a request for further comment on Tuesday.
Microsoft responded to Google's accusation by pointing out that users can easily change the default setting in the browser.
The EC could not be reached for comment on Tuesday. In March an EC spokesman said it had told Microsoft of its concerns about Windows Vista, although it had not launched a formal investigation. "We are concerned about the possibility that the...Vista operating system will include various elements which are currently available separately from Microsoft or other companies," an EC spokesman told Reuters.
Microsoft is already embroiled in a long-running antitrust case brought against it by the EC, but could face separate proceedings if the Commission decides Vista breaches competition laws.