The Bush administration on Wednesday asked a federal judge to order Google to turn over a broad range of material from its closely guarded databases.

The move is part of a government effort to revive an Internet child protection law struck down two years ago by the U.S. Supreme Court. The law was meant to punish online pornography sites that make their content accessible to minors. The government contends it needs the Google data to determine how often pornography shows up in online searches.

In court papers filed in U.S. District Court in San Jose, Justice Department lawyers revealed that Google has refused to comply with a subpoena issued last year for the records, which include a request for 1 million random Web addresses and records of all Google searches from any one-week period.

The Mountain View-based search and advertising giant opposes releasing the information on a variety of grounds, saying it would violate the privacy rights of its users and reveal company trade secrets, according to court documents.

Nicole Wong, an associate general counsel for Google, said the company will fight the government's effort ``vigorously.''

``Google is not a party to this lawsuit, and the demand for the information is overreaching,'' Wong said.

The case worries privacy advocates, given the vast amount of information Google and other search engines know about their users.

``This is exactly the kind of case that privacy advocates have long feared,'' said Ray Everett-Church, a South Bay privacy consultant. ``The idea that these massive databases are being thrown open to anyone with a court document is the worst-case scenario. If they lose this fight, consumers will think twice about letting Google deep into their lives.''

Everett-Church, who has consulted with Internet companies facing subpoenas, said Google could argue that releasing the information causes undue harm to its users' privacy.

``The government can't even claim that it's for national security,'' Everett-Church said. ``They're just using it to get the search engines to do their research for them in a way that compromises the civil liberties of other people.''

The government argues that it needs the information as it prepares to once again defend the constitutionality of the Child Online Protection Act in a federal court in Pennsylvania. The law was struck down in 2004 because it was too broad and could prevent adults from accessing legal porn sites.

However, the Supreme Court invited the government to either come up with a less drastic version of the law or go to trial to prove that the statute does not violate the First Amendment and is the only viable way to combat child porn.

As a result, government lawyers said in court papers they are developing a defense of the 1998 law based on the argument that it is far more effective than software filters in protecting children from porn. To back that claim, the government has subpoenaed search engines to develop a factual record of how often Web users encounter online porn and how Web searches turn up material they say is ``harmful to minors.''

The government indicated that other, unspecified search engines have agreed to release the information, but not Google.

``The production of those materials would be of significant assistance to the government's preparation of its defense of the constitutionality of this important statute,'' government lawyers wrote, noting that Google is the largest search engine.

Google has the largest share of U.S. Web searches with 46 percent, according to November 2005 figures from Nielsen//NetRatings. Yahoo is second with 23 percent, and MSN third with 11 percent.