The publisher of If I Did It: Confessions of a Killer, O.J. Simpson's hypothetical account of his ex-wife's slaying, says the book has hit No. 2 on the New York Times bestseller list for non-fiction.

Former Federal Reserve chair Alan Greenspan's Age of Turbulence tops the list, but If I Did It comes out ahead of former U.S. president Bill Clinton's book about philanthropy, Giving, on the ranking for the week ending Sept. 22, according to Beaufort Books.

O.J. Simpson, left, standing with his lawyer Yale Galanter, is arraigned in a Las Vegas court Sept. 19.
(Clint Karlsen/Associated Press)

The list will not appear in the New York Times until Oct. 7, but Beaufort released the figures ahead of time.

If I Did It is climbing up bestseller lists in both Canada and the U.S. after O.J. Simpson was arrested in connection with an alleged holdup in Las Vegas.

It is No. 7 on this week's bestseller lists for Chapters Indigo in Canada and Amazon.com in the U.S., which include both fiction and non-fiction.

On the New York Times list that appears this week and reflects sales for the first day of the book's sale, it is No. 3.

Beaufort said it has already printed 200,000 copies and plans another print run. No sales figures were given.

If I Did It is being published on behalf of the family of murder victim Ron Goldman, who died with Simpson's ex-wife, Nicole Brown Simpson, in 1994.

Simpson was acquitted of criminal charges in the murders but found liable in a "wrongful death" civil suit.

The ghost-written book purports to be Simpson's account of the murders.

The Goldmans initially objected to the publication of If I Did It and to Simpson benefiting financially from the book, but later sued for the rights to publication.

They have added a foreword and changed the title to If I Did It: Confessions of a Killer.

"We struggled with the concept of having to publish this book, but upon deeper reflection it became clear to us that this was the only opportunity to expose Simpson and offer some element of justice," Ron Goldman's father, Fred Goldman, said in a statement.

Proceeds from sale of the book go to a foundation set up in Ron Goldman's name.

"I like to hope that people are purchasing the book to be supportive of ... my family," Kim Goldman told Reuters, but acknowledged the public harbours a "morbid curiosity" about Simpson.

Simpson is free on bail of $125,000 US after being charged with kidnapping and robbery in connection with the alleged Las Vegas holdup.