The author, who uses a pseudonym, "was one of the first men through the door on the third floor of the terrorist leader's hideout and was present at his death," The Washington Post quoted a statement from Dutton, the New York-based publisher.
The book, No Easy Day: The Firsthand Account of the Mission That Killed Osama bin Laden, will be released on September 11.
If what the author says is true, the book would pull off the secrecy maintained by members of the team of Navy SEALs involved in the raid on bin Laden's compound in Abbottabad, Pakistan.
It could also raise legal and political issues for the Obama administration, which has carried out an aggressive crackdown on leaks even while it has also been accused of offering access to journalists and moviemakers to exploit the success of the bin Laden operation, the Post said.
It added that the Pentagon and CIA officials appeared to be caught off-guard by Dutton's announcement of the forthcoming book.
Officials indicated on Wednesday that neither the author nor the publisher had cleared the book's contents with the US defence department or the CIA, a step ordinarily required by former service members or spies seeking to write about classified operations.
"As far as we can determine, this book was not submitted for pre-publication review," said CIA spokesman Preston Golson.
Pentagon spokesman George Little said he was "unaware that anyone in the department has reviewed it". White House officials said they knew nothing of the book.
"We learned about this book today from press reports," said Tommy Vietor, spokesman for the National Security Council. "We haven't reviewed it and don't know what it says."