The National Party president is alleged to have brokered a confidentiality agreement with a woman who claimed she'd been harassed by former National Party MP Jami-Lee Ross.
The Herald has been told the deal was done sometime in the last two years.
Concerns have emerged that the party required the woman who complained about Ross' alleged harassment and bullying behaviour to sign a confidentiality agreement after she raised concerns with party bosses.
A source has told the Herald the deal was brokered by party president Peter Goodfellow.
The Herald put questions to the National Party tonight. A spokesman responded that Goodfellow had nothing further to add to a statement he issued earlier today, in which he said: "Any issues that we were aware of that were raised, were dealt with at the time. We have nothing further to add at this time."
Radio New Zealand reported that Goodfellow facilitated a "gentlemen's agreement" with a woman who complained about Ross' bullying behaviour, preventing her from speaking publicly about Ross' conduct.
That complaint was made a couple of years ago, about the time the agreement was struck. National leader Simon Bridges was not the party's leader at the time, RNZ reported.
The revelations follow a Newsroom report today detailing two anonymous women's "toxic" sexual affairs with Ross. Two others told the website they'd been harassed and bullied by the former Botany MP.
Ross issued a statement today saying he would not comment on the report and that he was assessing his legal options.
He also released text messages today relating to an alleged $100,000 donation. Ross has linked the donation to allegations of electoral fraud involving Bridges.
Bridges has denied any wrongdoing, labelling Ross, his former friend, a leaker, liar and a "terrible person".
Neither the texts nor a secret recording Ross released this week between him and Bridges have shown evidence of illegal activity.
But the recording was embarrassing for Bridges, capturing him referring to one of his MPs as "f...ing useless", forcing him to issue a public apology.