"None of us were aware the other person was going through the same thing. What do we do? So we talked about it — do we speak to the production company?" she said.
"They're not going to believe us. He's the big head star, they're going to keep him we're going to lose our jobs — because we're replaceable.
"And that's the disgusting thing about it, we all feel as though our voice isn't enough and we're not important enough."
Heynatz and fellow cast member Christie Whelan Browne both said they had approached production members with complaints.
Whelan Browne, who claimed McLachlan inappropriately touched and kissed her onstage, said she had gone to a senior production member saying McLachlan was "intimidating me on stage and others".
"She said, 'That's a very serious accusation'. The insinuation was — you don't want this to go any further," Whelan Browne said.
Claiming McLachlan had come into her dressing room and kissed her, Heynatz said she had also confided in a senior production member.
"The woman I shared this story with was really concerned and she really wanted me to feel safe at work," she said.
"She would look after me and every day she would come in and sit with until I was dressed and my hair was done, so that was kind of, she made sure that I was safe."
Heynatz said neither Whelan Browne nor fellow actress Angela Scundi, who also accused McLachlan, were among of the four women who she spoke with about the actor's alleged behaviour in 2014.
Though the actresses decided against making formal complaints at the time, considering the potential threat to their careers, Heynatz said fellow cast members started getting in touch years later when allegations started coming out about Hollywood heavyweight Harvey Weinstein and other entertainment industry figures.
While the Weinstein scandal prompted the women to seek legal representation and approach GFO, there is no suggestion the allegations levelled against McLachlan go beyond inappropriate touching. McLachlan vehemently denies all allegations.
"The Harvey Weinstein stories started coming out and I have an immediate physical and mental reaction to it," she said.
"I start reliving some of the sensory things that go on, feeling anxious and unsettled, sleeplessness."
Whelan Browne said she contacted Heynatz at the same time, despite not having been in touch for more than three years.
"I just said, 'Hey, I don't know if you're having any reaction to these stories that are coming out, but I am. I just wanted to see if you're OK.' She called me and apparently all the other girls had been talking," she said.
"I did feel a sense of shock when I heard what they'd been going through. And that they had talked about coming forward all those years ago, but, yeah, I'm glad that we were able to connect because for me it felt like a really lonely, solo experience and it doesn't anymore."
The three women who have gone on the record with complaints against McLachlan explained their decision, saying they hoped to change the culture of the industry that caused them to feel unable to come forward back in 2014.
"I hope that in coming forward, which is something that is very difficult and something I tried to avoid, but I hope that it makes a change," Whelan Browne said.
McLachlan has strenuously denied all allegations against him, saying in an email to Fairfax media the claims were "baseless" and "they seem to be simple inventions, perhaps made for financial reasons, perhaps to gain notoriety.
"These allegations are ALL made up," he said.
The theatre company behind GFO yesterday confirmed McLachlan would be stood down from his role in the current production of the show.
Production of The Doctor Blake Mysteries has also been put on hold "to allow due process", production company December Media announced Monday, and past episodes of the program have been removed from ABC's streaming platform iview.
Victoria Police confirmed on Monday complaints had been received concerning McLachlan's behaviour, and at least two more women have contacted police about the actor's behaviour since allegations were published.
