Book publishers and authors in most countries outside the US won a significant concession late on Friday as Google and American book industry representatives agreed to make changes to their landmark digital books settlement.

The amendments, disclosed in a legal filing in New York close to midnight on Friday, were made after strong objections from the governments of Germany and France, as well as complaints from book industry representatives from a number of other countries, including China.

Other revisions disclosed on Friday reflected complaints from the US Department of Justice, which had warned that the original plan raised "significant legal concerns". Its fears included the risk that the deal would give Google an effective monopoly in the emerging digital books business.

The new plan was immediately criticised as a "sleight of hand" by the Open Book Alliance, a consortium of Google's opponents including Microsoft and Amazon.

"None of the proposed changes appear to address the fundamental flaws illuminated by the Department of Justice and other critics that impact public interest," said Peter Brantley, director of the Internet Archive, which is creating its own online digital archive.

If the revised deal wins court approval, it will make millions of out-of-print works that could previously only be found in a handful of university research libraries available online. While objecting to some aspects of the original plan, which was reached a year ago, the US justice department had applauded the settlement's aim, since it had "the potential to breathe life into millions of works that are now effectively off limits to the public".