Reid said one of the women who worked in the same political circles as Ross, a married MP, said she had an affair with him after constant and repeated pressure.
Reid told RNZ this morning that the women "got under the spell of" Ross.
"They were in a power control, a manipulation sort of situation," she said.
Reid said Ross was feared and he had "seriously harassed and bullied" the individuals in question.
"Some of them to the point where they have had to take leave from their work and get medical attention."
Reid said when Ross stood up on Monday and talked about his "moral compass and being comfortable with his behaviour", that became a "tipping point", for the individuals.
Reid has been working on this story for a while – "way before the situation this week".
She said her sources wanted to come forward sooner, but were "frightened".
"They have come forward now because he said 'I have never disrespected a woman, I have been brought up by my grandmother and mother to respect women.'
"That has been a bit of a tipping point for them to go public, even though they're anonymous."
Reid said there were men she spoke to, as well as women, who felt they have been seriously threatened and bullied by Ross.
"There was a lot of talk from him like 'I'm going to take you out politically' or 'I'm going to destroy your career'."
Newsroom broke the story about Ross' alleged infidelity.
Two of the relationships were sexual, the website says. Some of the women, who are not identified, felt "manipulated and intimidated" by Ross, while others felt pressured not to speak out.
Ross has been contacted for comment this morning.
One of the women, who said she had a sexual relationship with the MP, said Ross had told her his marriage was "on the rocks" and promised their relations would remain secret.
"Initially it was euphoric but I knew it was wrong," she told Newsroom, describing Ross as a "narcissist".
"It was like a fairy tale. I'd found this person, this soulmate, who provided meaningful advice … he always knew what to do. Looking back, it was nothing but a game."
But things changed after Ross began asking where she had been and who she had been with, she said.
"He would fly into jealous rages, arguing endlessly. That's when the abusive part of the relationship started to outweigh the love-bombing. I would think, 'Why can't I get this right? Why can't I communicate in a way that pleases him?'"
After that, sex between the two devolved to "brutal" and "misogynistic" and woman said she was barely able to function.
