“There is a certain irony that, by filing and publicizing this lawsuit, plaintiffs have brought more attention upon themselves than O’Reilly’s comments, which were never directed at or referred to plaintiffs, ever did,” lawyers for Mr. O’Reilly said. They added that Ms. Mackris and Ms. Diamond had violated their confidentiality agreements — “Mackris by inviting a New York Times reporter and photographer into her home, and Diamond through social media.”

“O’Reilly will, in the proper, arbitral forum, assert claims against Mackris and Diamond for breach of these agreements,” his lawyers said.

According to court documents filed Tuesday, Mr. O’Reilly said that the defamation claims were “frivolous and wholly unsupported in law or fact” and that none of his statements would expose the women to “public shame or ridicule.”

“O’Reilly’s statements consist of his opinions concerning the unbalanced journalism that went into stories published about him and his critique of the advocacy groups that organized a sponsor boycott against him and his top-rated show,” his lawyers said. “Such statements of opinion are protected and cannot serve as a basis for a defamation claim.”

In the lawsuit, the women said that Mr. Murdoch had disparaged and defamed them during an interview with Sky News in London, during which he characterized sexual harassment issues at Fox News as being isolated to Roger Ailes.

The women also took issue with the company’s statement that “no current or former Fox News employee ever took advantage of the 21st Century Fox hotline to raise a concern about Bill O’Reilly.”

Lawyers for Fox News said in the court filing Tuesday that the network could not be held liable for the statements made by its parent company or Mr. O’Reilly. They added that statements by 21st Century Fox and Mr. Murdoch were not defamatory because they had not “mentioned any of the plaintiffs, provided any details of their settlements, or cast any doubt on the merits of their claims.”

Lawyers for Mr. O’Reilly and the network said they had not breached Ms. Bernstein’s settlement agreement because Mr. O’Reilly was not a party to the agreement and there was “no allegation that Fox News disclosed anything about Bernstein’s settlement or the facts leading up to it.”