NEW YORK - One-time book publishing powerhouse Judith Regan filed a $100 million defamation lawsuit Tuesday saying her former employers asked her to lie to federal investigators about Bernard Kerik, the former police commissioner who was once her lover, and tried to destroy her reputation.

Regan, who worked for HarperCollins Publishers LLC, said the smear campaign stems from her past intimate relationship with Kerik, who was police commissioner under former Mayor Rudolph Giuliani, and from the political agenda of News Corp., the parent company of HarperCollins.

Regan, 54, says in court papers that News Corp.'s political agenda centers on Giuliani's presidential ambitions. It was Giuliani, a Republican, who appointed Kerik police commissioner and recommended him to President Bush for secretary of the Department of Homeland Security.

Kerik had to withdraw his nomination after it was revealed he had not reported the wages he paid to a nanny.

Regan says "it is now widely accepted" that one of Giuliani's vulnerabilities is the 52-year-old Kerik. Because of Regan's affair with Kerik, court papers say, a senior News Corp. executive told her he believed she had information about Kerik that could hurt Giuliani's campaign and she should lie to federal investigators.

Court papers say another executive told Regan, a HarperCollins editor for 12 years, to withhold documents that were clearly relevant to the government's investigation of Kerik.

News Corp. spokesman Howard Rubenstein said of Regan's lawsuit, "The claims are preposterous."

Kerik, who married his current wife in 1998 and has two children with her, apparently began his affair with Regan in 2001 while writing "The Lost Son," in which he described being abandoned by his prostitute mother. He pleaded not guilty Friday to a wide-ranging indictment charging him with conspiracy, corruption and tax evasion.

Regan's lawsuit says, "defendants knew they would be protecting Giuliani if they could preemptively discredit her."

Regan, known for such provocative best-sellers as Jose Canseco's "Juiced" and Jenna Jameson's "How to Make Love Like a Porn Star," sued nearly a year to the day that the world learned of the project that helped end her reign at HarperCollins: "If I Did It," O.J. Simpson's hypothetical confession to the killings of Nicole Brown Simpson and Ronald Goldman.

The book was soon pulled in response to public outrage, and Regan's standing at News Corp. was irreparably damaged. Goldman's family eventually acquired rights to "If I Did It," which became a best-seller after being published by Beaufort Books.

In December 2006, court papers say, Regan was fired with more than two years left on her contract. The defendants said she had made anti-Semitic remarks while talking to an in-house HarperCollins lawyer, Mark Jackson, her court papers say.

"This charge was completely fabricated," her court papers say in bold print.

They say a temporary secretary who set up the call and remained on the line confirmed that Regan never made any such comments.

"Defendants knew their allegations of anti-Semitic comments were false and they were manufactured to create a pretext for Regan's termination and further undermine her credibility," Regan's court papers say.

Her papers say that contrary to the defendants' accusations, she "did not refer to a 'Jewish cabal' during her Dec. 15, 2006, call with the attorney "nor did she make any anti-Semitic remarks."

Regan's lawsuit says the statements were defamatory "because they injure Regan's professional name and reputation by charging her with making anti-Semitic comments, by implying that she is deceitful, unethical and without integrity."