Warning: This article contains descriptive sexual language and may be triggering for some people.
Newsroom reporter Melanie Reid says she knows of "at least another five" women with stories to tell about Jami-Lee Ross.
Newsroom on Thursday morning quoted four women accusing the outgoing National MP of being a narcissist who used "brutal sex" to "dig dirt" on others.
Two allegedly had affairs with Mr Ross, and the other two detailed their "toxic working environment".
Ms Reid, who wrote the article after investigating Mr Ross' behaviour for a year, told The AM Show they're not the only women with complaints against the 32-year-old Botany MP.
"There are more women who have had affairs with him," she told host Duncan Garner. "There's at least another five I know of… We're talking about a number of affairs over a long period of time."
The explosive - but unproven - allegations were revealed the day after Mr Ross released a recording he claims proves National leader Simon Bridges broke the law.
One woman told Newsroom she was "targeted in a systematic and calculated way", and their affair soon evolved into "jealous rages", "brutal and misogynistic sex" and "a living hell".
"There were multiple times I tried to leave only to be hoovered back in through fear," the unnamed woman told Newsroom. "The fear of him ruining my reputation, but mainly the fear of the unknown."
She said his motivation was a "lust for power and control" - echoing comments Mr Ross made about Mr Bridges. The affair allegedly ended just as the #MeToo wave came, late last year.
A second women said Mr Ross used her to "dig dirt" on his National Party colleagues.
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"It's a mind f**k... and it was easy to be swept away. I was sucked in and swept sideways despite my better judgment. It's not like he's drop-dead gorgeous and has a hot body or anything."
He allegedly told her to sleep with other men in Parliament, including MPs, Newsroom reports.
A third woman, reportedly a National Party member, said she has never been "more harassed and disrespected as a woman in my whole life" after dealing with Mr Ross.
She said she stayed quiet "out of respect for the party", but had to talk after Mr Ross' denials of wrongdoing in his hour-long press conference on Tuesday.
"This man is a narcissist. He absolutely turns on people when he doesn't get his own way. He is a master manipulator and a deceitful liar who has no problem looking somebody in the eye and outright lying."
The fourth woman says Mr Ross "destroyed" her as a person, and she had to seek help for the stress and anxiety he allegedly caused.
"I lost my self-esteem... I lost everything."
Ms Reid told The AM Show that beyond the alleged affairs, the story comes down to the “misuse of power”.
“This story is not really, for me, about affairs. This story is about the misuse power and the mistreatment of women.”
Mr Ross did not respond to Newsroom's request for a response. Newshub has contacted Mr Ross.
Earlier this week he said Mr Bridges and Ms Bennett had accused him of harassing four women - the exact number quoted in the Newsroom article. Mr Bridges allegedly told him that number could be increased to 15.
On Tuesday, Ms Bennett told NZME the leadership team raised issues with Ross - but it wasn't about harassment.
"At no point was the matter of sexual harassment ever put to Jami-Lee Ross," Bennett told NZME. "What was put to him was inappropriate behaviour that is unacceptable from a married Member of Parliament."
Watch the full call with Melanie Reid above.
The AM Show with Duncan Garner, Amanda Gillies and Mark Richardson, weekdays 6-9am on RadioLIVE and streaming live to the rova app on Android and iPhone.