A US judge agreed on Monday to extend the deadline for Google and US authors and publishers to submit a revised settlement that would clear the way for millions of books to be sold online.

Judge Denny Chin, who is presiding over the legal agreement between Google and authors and publishers, approved a request for the modified settlement to be submitted on Friday instead of on Monday as originally scheduled.

In a letter to the court on Monday, the parties said they have been "working diligently" to hammer out an amended settlement agreement but needed more time.

They said they held talks as recently as Friday with the US Justice Department, which raised objections to the original version of the legal settlement because of copyright and anti-trust issues.

Google and the Authors Guild and the Association of American Publishers reached the settlement last year to a copyright infringement suit they filed against the Mountain View, California, company in 2005.

Under the settlement, Google agreed to pay 125 million dollars to resolve outstanding claims and establish an independent "Book Rights Registry," which would provide revenue from sales and advertising to authors and publishers who agree to digitize their books.

Rival technology companies, privacy advocates, consumer watchdog groups and the French and German governments are among those who have filed objections to the settlement with the US District Court in New York hearing the case.

Chin is expected to hold a so-called "fairness hearing" in late December or early January on whether or not to approve the settlement.