She also says Giuliani owes her nearly $US2 million ($A3 million) in unpaid wages.

Noelle Dunphy said in the lawsuit she was Giuliani's business development director and public relations consultant from 2019 to 2021. She initially made her allegations public in January, but she detailed her claims further in a 70-page legal complaint filed on Monday in New York.

Giuliani "vehemently" denied the allegations through a spokesman. His lawyer had also previously denied that Dunphy ever worked for Giuliani.

"Mayor Giuliani's lifetime of public service speaks for itself, and he will pursue all available remedies and counterclaims," said Giuliani's communications adviser, Ted Goodman.

The new court filing portrays Giuliani, 78, as a hard-drinking, Viagra-popping womaniser who made satisfying his sexual demands "an absolute requirement of her employment." She is seeking at least $US10 million ($A15 million).

Dunphy claimed in the lawsuit to have made numerous audio recordings of Giuliani, including some in which she says he can be heard making sexual comments, demanding sex and making sexist, racist, and antisemitic remarks.

Dunphy's legal team declined a request from The Associated Press to share those recordings, saying they were part of the litigation.

Included in the complaint are screenshots of suggestive text messages purportedly from Giuliani.

The lawsuit claims Giuliani hired Dunphy in January 2019 and promised to pay her $US1 million ($A1.5 million) per year for her consulting work. But he told her that he had to defer paying her until he settled his divorce from his third wife, Judith, according to the lawsuit.

Almost immediately, according to the complaint, Giuliani started making sexual advances, including kissing her in the back of an SUV on her first day and demanding that she take care of him sexually, sometimes while he was on the phone with high-profile friends and clients.

Often, Dunphy alleges, Giuliani would demand she work in a bikini or in American flag-themed shorts he bought for her, and he urged her to strip naked for him during video meetings.

Giuliani reached a divorce settlement in December 2019, but Dunphy said all she got from Giuliani were a few cash payments totaling $US12,000 ($A18,000) to cover living expenses. He still owes her $US1,988,000 ($A3 million), she said.

Dunphy also contended that Giuliani had reneged on a promise to represent her, for free, in a protracted legal fight involving claims of domestic violence.

In that legal fight, Dunphy had accused a romantic partner of raping her and throwing her down a flight of stairs. The man she sued filed a counter lawsuit, saying he was the one being physically assaulted and harassed. He also sued for defamation, saying he was being extorted.

Dunphy agreed to accept $US10,000 ($A15,000) to settle her claims in 2016. But the two sides were still fighting over a final resolution as recently as last year.

The Associated Press does not typically identify people who say they are victims of sexual abuse unless they grant permission, as Dunphy has done.

Australian Associated Press