Google is fighting with the US government over a request for the search engine giant to provide information on people looking for pornography online.

The government claims to need Google usage records to prepare its defence in a lawsuit brought against it by the American Civil Liberties Union (ACLU). But Google is resisting.

As a result, Attorney General Alberto Gonzales filed a motion to compel Google to comply with a government's subpoena.

The ACLU lawsuit, filed in 1998, challenges the Child Online Protection Act (COPA) law, which aims to protect minors from the effects of exposure to sexually explicit material on the Internet.

The ACLU argues that COPA violates the First Amendment. A district court granted its motion for preliminary injunction, and an appeals court affirmed it in 2000.

The case went to the US Supreme Court, which disagreed with the appeals court and sent the decision back to the district court. That court then agreed with its preliminary injunction all over again. The Supreme Court reviewed the case again, this time agreeing with the injunction, and sent the case back for trial.

As such, the government is now preparing its defence of COPA, specifically trying to buttress its contention that the law is more effective than filtering software in protecting minors from pornographic material on the Internet.

As a result, the government has issued subpoenas to Google and other search engines requesting information to make its case. But Google has refused to comply with two requests. One is that Google provide the government with a "random sample" of one million website addresses found in Google's search engine index and the other is that it provide the government with the text of all queries filed on the search engine during a specific week.

"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," the motion filed reads. This information would help the government understand how often Web users encounter material considered "harmful to minors" as a result of using a search engine, and to determine how effective filtering software is, according to the motion.

Google's lawyer, Nicole Wong, said in a prepared statement: "Google is not a party to this lawsuit and their demand for information overreaches. We had lengthy discussions with them to try to resolve this, but were not able to and we intend to resist their motion vigorously."