By Michelle Nichols

NEW YORK (Reuters) - A lawyer for Tom Cruise on Monday attacked an unauthorized biography of the high-profile Scientologist, calling it "outrageous, sick stuff," even as U.S. publisher St Martin's Press defended the book.

"Tom Cruise, An Unauthorized Biography," by British author Andrew Morton, best known for his top-selling 1992 book on Princess Diana, is due on U.S. bookshelves this month.

"His book is a rehash of tired old lies about Tom and his religion, some new grotesque lies, like the sick comparison of his child to 'Rosemary's Baby' and the nutty assertion that he's the No. 2 head of the Church of Scientology," Cruise's longtime lawyer, Bert Fields, told Reuters.

"He (Morton) has made a number of claims that are false and demonstrably so," said Fields, who added that he had read Morton's book, "Clearly the book is actionable, but I'm not commenting on anything to do with legal issues."

The Church of Scientology in London did not reply to an e-mail asking for comment on the allegations. Scientology was founded by science fiction writer L. Ron Hubbard in Los Angeles more than 50 years ago.

In a brief statement on Monday, St Martin's Press spokesman Steve Troha said: "We stand by our book and our author."

Fields said Cruise has no plans to read the book, and the lawyer also slammed Morton's claims that Cruise's former wife, Australian actress Nicole Kidman, was worried she would be blackmailed or not see the couple's two adopted children if she spoke out against Scientology after their divorce.

Kidman's spokeswoman was not immediately available for comment, but Fields said Morton's claims were "absolute hogwash ... what they say about her is absolutely false."

"The man should be ashamed of himself and so should his publisher," said Fields. "He pretends to be writing a biography without ever talking to anybody who has really known Tom for the past 30 years."

According to www.scientology.org, Scientology "is the study and handling of the spirit in relationship to itself, others and all of life. The religion comprises a body of knowledge extending from certain fundamental truths."

Those fundamental truths include man being an immortal, spiritual being whose experience "extends well beyond a single lifetime."

Germany does not recognize Scientology as a religion and regards it as a cult masquerading as a church to make money. Scientologists reject this view.