Authors are split over the deal
Amazon has urged a New York court to reject a deal that would allow Google to build a vast digital library.
The online retailer says that if Google is given exclusive rights to scan books for use on the internet, it is "likely to lead to a monopoly".
Interested groups and authors have until 28 January to file objections to the project to a US court.
Google says the project will "unlock access to millions of books" and give authors new ways to distribute books.
Google Books aims to scan millions of books worldwide and make them available - and searchable - online.
It was first launched in 2004 but was put on hold a year later when the Authors Guild of America and Association of American Publishers sued over "massive copyright infringement".
As a result, in 2008 Google agreed to pay $125m (£77m) to create a Book Rights Registry, where authors and publishers could register works and receive compensation.
A decision on whether the deal could go through was originally scheduled for early October.
But, the presiding Judge sent the deal back to the drawing board after criticism and objections from around the world.
Groups have until 28 January to file objections to the revised settlement to a US court, which will decide whether to approve it. Authors have the same deadline to opt-out of the project.
A fairness hearing has then been set for 18 February.
In the run up to the deadline, industry and authors have once again started mounting pressure on Google.
Fantasy writer Ursula K Le Guin has asked for the US to be excluded from the project.
In an open letter to Judge Denny Chin, who will preside over the hearing, Ms Le Guin expresses concern about the "opt-out" clause in the settlement, which she says "disguises an assault on authors' rights".
It means that unless authors in certain countries specifically do not give their permission, their books will be scanned and eventually sold in digital form by Google Books, who will share a percentage of the revenue.
"Google, like any other publisher or entity, should be required to obtain permission from the owner to purchase or use copyrighted material, item by item," she wrote.
Her letter has been signed by 365 other authors also concerned about the plan.
In addition, Ms Le Guin says that the National Writers Union, the American Society of Journalists and Authors and the Science Fiction and Fantasy Writers of America are against the proposed settlement.
However not all authors oppose Google's proposals. Amy Tan, Simon Winchester and the heir of John Steinbeck are among those who support the move.
"If approved by the court, this settlement stands to unlock access to millions of books in the US while giving authors and publishers new ways to distribute their work," said a Google spokesperson.