Two women have anonymously told Newsroom they had affairs with embattled politician Jami-Lee Ross, while two others said they were subjected to emotional abuse and bullying by him.
The four women variously said they felt intimidated, manipulated, abused or groomed while working with him, and spoke on condition of anonymity.
Mr Ross has not yet returned calls from 1 NEWS seeking comment on the allegations.
Amongst the allegations at Mr Ross' extraordinary news conference on Tuesday was a claim that National Party leaders had accused him of harassing four women. "I strenuously deny allegations that I have harassed anyone," Mr Ross said at the time.
One of the women told Newsroom she first slept with Mr Ross at a National Party event after developing a work friendship with him.
The woman said Mr Ross initiated late-night texting with her and the sexual encounters were consensual, but said she believes he "groomed" her to get information on other National Party members.
She said she knew he was married, but he had stopped wearing his wedding ring and that there was confusion as to where things were at with him and his wife.
The woman said the relationship eventually devolved into "incoherent rages and brutal sex".
A second woman also said she had an affair with Mr Ross, and described him as a narcissist.
She said Mr Ross had told her his marriage was "on the rocks" and insisted no one would know.
A third woman said she was subjected to harassment and intimidation by the former MP.
"During the past two years, I can assure the public that my dealings with Jami-Lee Ross have never left me more harassed and disrespected as a woman in my whole life," she told Newsroom.
A disagreement between the two led to a personal campaign against her, she said.
"He said he would go to war with me and my family and told me, 'You are throwing away your career.'
"It was relentless and ongoing. Verbal threats. Intimidation. Lies, rumours to discredit me both personally and professionally.
"Manipulation of other party members to publicly embarrass me, statements to both myself and my friends which implied physical threats to myself and my family."
A fourth woman said she worked with Mr Ross and was "nearly destroyed" by his workplace conduct.
"Not only was he rude and arrogant, he falsely accused me of things I didn’t do. He really didn’t treat me fairly," she said.
"He was setting me up and I knew I hadn’t done the things he said I had ... I lost my self-esteem … I lost everything.
"I could have easily had a personal grievance case but I chose not to expose myself and the National Party for whom I had great respect."
The woman said she later sought medical help for the stress and anxiety caused by working with Mr Ross.
Mr Ross said yesterday that he was "comfortable with my moral judgement" and "comfortable with all of my conduct".
He married wife Lucy Schwaner in 2008.
He did not respond to requests for comment on these allegations when approached by Newsroom.
Newsroom Investigations Editor Malanie Reid this morning told TVNZ1's Breakfast programme that the final straw for the women which prompted them to participate was Mr Ross's comments yesterday to media.
"Everyone seemed pretty scared and fearful of coming forward," she said.
"When Jami-Lee Ross came out at this press conference and specifically said I was brought up by my mother and grandmother to respect women ... it was a tipping point."
National Party MP Maggie Barry responded by calling the article a "portrait of a kamikaze narcissist".
"Required reading for anyone who wants to understand this dishonest, manipulative and totally untrustworthy piece of work."