Google has argued that turning over more than a million of its search records to the U.S. government would undermine users' trust in its service and compromise its trade secrets.

Arguing against a government subpoena that seeks a week's worth of search data from the company, Google also argued that the request places an undue burden on it and asked the district court in San Jose, California, to reject the government's motion forcing Google to comply.

"Google users trust that when they enter a search query into a Google search box, not only will they receive back the most relevant results, but that Google will keep private whatever information users communicate absent a compelling reason," the company's lawyers wrote in court papers filed Friday.

"The Government's demand for disclosure of untold millions of search queries submitted by Google users and for production of a million Web page addresses or 'URLs' randomly selected from Google's proprietary index would undermine that trust, unnecessarily burden Google, and do nothing to further the Government's case in the underlying action."

The U.S. Department of Justice (DOJ) requested the information in August last year. It says it wants it to use in a separate case, to help determine whether a federal law called the Child Online Protection Act (COPA) is more effective than filtering software in preventing minors from accessing harmful material on the Internet.

Yahoo, Microsoft's MSN division and America Online were issued with similar subpoenas and all complied with the request to some degree. The government says the search data is not tied to individual users and will not reveal people's individual search habits.

The DOJ has until Feb. 24 to respond to Google's arguments. A hearing in the case, brought by U.S. Attorney General Alberto Gonzales, is set for March 14.

The DOJ is defending COPA in a 1998 suit filed by the American Civil Liberties Union, which says the law violates the U.S. Constitution's First Amendment right to freedom of speech.