Since that incident in the early 1990s, Henstridge has found success as an actress – starring in the films Species and The Whole Nine Yards. But she said she has carried the memory of the run-in with her, and watched from afar as Ratner became one of Hollywood’s most powerful players – directing, producing or financing dozens of today’s biggest box-office hits, including Rush Hour, X-Men: The Last Stand, The Revenant and Horrible Bosses.

As hundreds of women have come forward in recent weeks with allegations of sexual misconduct at the hands of producer Harvey Weinstein, director James Toback and numerous other powerful men, Henstridge decided she would no longer remain silent.

In interviews with the Los Angeles Times, Henstridge and five other women accused Ratner of a range of sexual harassment and misconduct that allegedly took place in private homes, on movie sets or at industry events. As is often the case, none of the women reported the allegations to the police.

On Ratner’s behalf, Singer “categorically” disputed their accounts.

“I have represented Mr Ratner for two decades, and no woman has ever made a claim against him for sexual misconduct or sexual harassment,” Singer said in a 10-page letter to The Times. “Furthermore, no woman has ever requested or received any financial settlement from my client.”

Olivia Munn said that while visiting the set of the 2004 Ratner-directed After the Sunset when she was still an aspiring actress, he masturbated in front of her in his trailer when she went to deliver a meal. Munn wrote about the incident in her 2010 collection of essays without naming Ratner. On a television show a year later, Ratner identified himself as the director, and claimed that he had “banged” her, something he later said was not true. The same year her book was published, Munn ran into Ratner at a party thrown by Creative Artists Agency and he boasted of ejaculating on magazine covers featuring her image, she told The Times.

She said that persistent false rumours that they had been intimate have infuriated her, prompting her to talk to The Times in support of other women who are “brave enough to speak up”.

“I’ve made specific, conscientious choices not to work with Brett Ratner,” Munn said.

“It feels as if I keep going up against the same bully at school who just won’t quit,” she said. “You just hope that enough people believe the truth and for enough time to pass so that you can’t be connected to him anymore.”

Recalling the incident, Munn said she entered Ratner’s trailer and quickly placed the food on a table. She said she was startled to find him inside. She tried to make a quick exit, but Ratner implored her not to leave.

“He walked out … with his belly sticking out, no pants on, shrimp cocktail in one hand and he was furiously masturbating in the other,” Munn said. “And before I literally could even figure out where to escape or where to look, he ejaculated.”

Munn said she let out a “startled scream” and raced out of the trailer. She said she immediately told the man who had asked her to deliver the food. His reaction? “It wasn’t a shock. It wasn’t surprise,” Munn recalled. “It was just, ‘Ugh, sorry about that.’”

Ratner “vehemently disputes” Munn’s allegations, Singer said.

Ratner, 48, has long flaunted his playboy persona, bragging publicly about his sexual prowess. He has been romantically linked to the likes of Paris Hilton, Lindsay Lohan and Mariah Carey. In December, Tina Fey, speaking at the Hollywood Reporter’s annual Women in Entertainment breakfast, cracked: “Brett Ratner is here. In his defence, he thought this was a thing where you could eat breakfast off of 100 women.”

In interviews, Ratner has tried to smooth out the rough edges of his bad-boy image, especially more recently, as he has expanded his business ventures. In 2012, Ratner cofounded production company RatPac Entertainment. A year later, RatPac partnered with now-Treasury Secretary Steven Mnuchin’s Dune Entertainment to create the investment vehicle RatPac-Dune Entertainment, which inked a co-financing deal with Warner Bros. worth about US$450 million. Among Ratner’s executive producing credits via those companies are Jersey Boys and Black Mass.

The filmmaker often has told reporters that he doesn’t use drugs or drink alcohol. Sometimes, in enumerating his lack of vices, Ratner also points out his love of beautiful women, saying, for example, in a 2008 Jewish Journal story: “I’m not into dark stuff. I’m just a nice Jewish kid … who loves movies and pretty girls.”

Actress Jaime Ray Newman said Ratner put it more bluntly to her, explaining in vulgar terms that he needed sex – not alcohol or drugs.

Newman said she encountered Ratner in 2005 when they were both in first class on an Air Canada flight. The filmmaker swapped seats with his assistant before departure so he could be next to her, she said. Newman, who was on her way to shoot her first major acting role on the TV show Supernatural, was excited to talk with a “famous director” about to helm X-Men: The Last Stand, she said.

Within five minutes of the plane taking off, she said, Ratner began loudly describing sex acts he wanted to perform on her in explicit detail. He also showed her nude photos of his then-girlfriend, said Newman, 39, who stars on Netflix’s forthcoming The Punisher.

“He was graphically describing giving me oral sex and how he was addicted to it,” she said.

Newman said she was so shaken by the encounter that she immediately told a handful of people about it. Both her mother and a friend confirmed to The Times that the actress shared details shortly after the flight.

Ratner, through his lawyer, denied that the incident occurred, referring to it as a “ridiculous claim”.

Actress Katharine Towne also described an aggressive come-on by Ratner that left her so uncomfortable that she said she still vividly remembers the incident years later. She said she met the director in L.A. around 2005 at a party in a film star’s home, where he made unwanted advances. Ratner, she said, was persistent, “making it evident that he had one motive” – to sleep with her.

“He started to come on to me in a way that was so extreme,” said Towne, 39, whose credits include the film What Lies Beneath. The actress, who is the daughter of Chinatown screenwriter Robert Towne, excused herself. Ratner followed her into a bathroom.

“I think it’s pretty aggressive to go in the bathroom with someone you don’t know and close the door,” Towne said.

She said she was nervous, and tried to make a joke about her weight: “I don’t even know what you want with me. I’m kind of chubby right now.”

He was undeterred. “I like ‘em chubby sometimes,” she said Ratner replied. Towne gave Ratner her number, hoping to placate him. Ratner’s assistant called her for the next six months, unsuccessfully trying to arrange a dinner for her and the filmmaker, she said.

Ratner’s lawyer Singer called Towne’s account “absurd”.

“Even if hypothetically this incident occurred exactly as claimed, how is flirting at a party, complimenting a woman on her appearance, and calling her to ask her for a date wrongful conduct?” Singer said.

Although some have questioned his conduct, Ratner has defenders in the industry including five former assistants who have worked closely with him throughout the years. David Steiman, Hopi Dobuler, Drew Sherman, Brett Gursky and Izak Rappaport all said that they did not witness him misbehave and praised him as a boss and mentor.

Steiman, who was Ratner’s assistant from 1999 to 2004, said he never saw him mistreat women, and would be “shocked” if such conduct occurred. Steiman noted that Ratner dated actress Rebecca Gayheart and tennis star Serena Williams during his time working for the filmmaker.

Said Dobuler, a longtime former assistant to Ratner: “I think he’s great. … He’s a family guy.”