Google is suing the U.S. Department of the Interior over a request for bids for a new e-mail and messaging solution it says favors rival Microsoft.
The search giant filed the suit with the U.S. Court of Federal Claims on Friday.
Google Inc. alleges that in August, the government put out a request for bids that limits respondents to use Microsoft Corp.'s business productivity software, which was designed for the federal government.
Google called the specification "unduly restrictive" and in violation of the Competition in Contracting Act.
It said in a statement that an open process "could save U.S. taxpayers tens of millions of dollars and result in better services." Google presented a solution using Google Apps.
Interior spokeswoman Kendra Barkoff declined to comment.