Lawyers for the Justice Department and Google were expected to elaborate on their opposing views in a hearing in San Jose scheduled on Tuesday before US District Court Judge James Ware.

It will mark the first time the Justice Department and Google have sparred in court since the government subpoenaed the California-based company last summer in an effort to obtain a long list of search requests and website addresses.

The government believes the requested information will help bolster its arguments in another case in Pennsylvania, where the Bush administration hopes to revive a law designed to make it more difficult for children to see online pornography.

Google has refused to co-operate, maintaining that the government's demand threatens its users' privacy as well as its own closely guarded trade secrets.

The Justice Department has downplayed Google's concerns, arguing it does not want any personal information nor any data that would undermine the company's thriving business.

The case has focused attention on just how much personal information is stored by popular websites like Google - and the potential for that data to attract the interest of the government and other parties.

'Invasive requests' 

Time Warner's American Online
is another site involved in issue

Although the Justice Department says it does not want any personal information now, a victory over Google in the case would likely encourage far more invasive requests in the future, said University of Connecticut law professor Paul Schiff Berman, who specialises in internet law.

"The erosion of privacy tends to happen incrementally," Berman said.

"While no one intrusion may seem that big, over the course of the next decade or two, you might end up in a place as a society where you never thought you would be."

Google seized on the case to underscore its commitment to privacy rights and differentiate itself from the internet's other major search engines - Yahoo Inc, Microsoft Corp's MSN and Time Warner Inc's America Online.

All three say they complied with the Justice Department's request without revealing their users' personal information.

Co-operating with the government "is a slippery slope and it's a path we shouldn't go down," Sergey Brin, Google co-founder, told industry analysts earlier this month.

China's capitulation

Even as it defies the Bush administration, Google recently bowed to the demands of China's Communist government by agreeing to censor its search results in that country, so it would have better access to the world's fastest growing internet market.

"The erosion of privacy tends to happen incrementally"

Paul Schiff Berman,
Law professor, University of
Connecticut

Google's China capitulation has been harshly criticised by some of the same people cheering the company's resistance to the Justice Department subpoena.

The Justice Department initially demanded a month of search requests from Google, but subsequently decided a week's worth of requests would be enough.

In its legal briefs, the Justice Department has indicated it might be willing to narrow its request even further.

Ultimately, the government plans to select a random sample of 1000 search requests previously made at Google and re-enter them in the search engine, according to a sworn declaration by Philip Stark, a statistics professor at the University of California, Berkeley who is helping the Justice Department in the case.