The department has opposed a revised legal settlement reached between Google and the American authors and publishers that would allow it to scan and sell millions of books online.
In an opinion filed in a New York Federal Court on Thursday, the justice department said the amended settlement raises anti-trust concerns.
"The amended settlement agreement suffers from the same core problem as the original agreement: it is an attempt to use the class action mechanism to implement forward-looking business arrangements that go far beyond the dispute before the court in this litigation," the department of justice said in its statement in the court.
The government action is a major set-back to Google's efforts to win approval of a 15-month old legal settlement that would make it a store house for millions of books.
The Justice department's advise to the court comes even as consumer watchdogs, literary agents, foreign governments and state governments in US have already filed objections before a US district judge to reject the agreement.
Judge Denny Chin is to hold a hearing on February 18 to consider approving the class action settlement.
But the justice department said that the United States remains committed to working with the parties on the issues concerning the scope and content of the settlement.
In its 26-page statement filed in the court, the department patted the settlement for having made substantial progress, but said it infringed on the US copyright law and raised concerns that Google's partnership with the US publishers would amount to forming a literary cartel.
Despite opposing the settlement, the justice department has urged the parties to have another go by making suitable changes to eliminate legal concerns.
Reacting to the government's opposition, Google, which is embroiled in a dispute with China, defended the agreement saying this could lead to unlocking access to million of books.
Google in 2008 had reach a settlement with the Authors Gill and Association of American publishers to pay $125 million to resolve all outstanding claims and to establish and an independent registry of books.
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