Colin Craig is seeking compensation for alleged defamatory comments made by the "dirty politics brigade".
At a press conference this afternoon, the former Conservative leader said he was suing Jordan Williams, John Stringer and Cameron Slater for $300,000, $600,000 and $650,000 respectively.
At the conference he held up a booklet, titled Dirty Politics and Hidden Agendas, which he claimed outlined a "campaign of defamatory lies" against him.
Mr Craig claimed it did not do the country well to have a group of people influencing public opinion through a "web of deceit and media manipulation".
"Today the line is drawn. Either the dirty politics brigade is telling the truth or I am."
He also revealed he had questioned his sanity amidst all the "dirty politics" allegations but says he still cared about the Conservative Party.
Mr Craig has vehemently denied all allegations against him, including sexual harassment, payouts against victims and sexually explicit texts. He has previously denied sexual harassment claims involving his former press secretary, Rachel MacGregor.
Mr Craig said that formal claims were being prepared and would be served to the three in question within the next 48 hours.
His wife, Helen, spoke out in support of her husband, saying: "This is about who you can trust...and you can trust my husband, he is a good and trustworthy man. He has and will continue to have my full and unwavering support."
Mr Craig in the booklet he was releasing he outlined what he saw as the "strategy" to remove him as leader of the Conservative Party.
He has also blamed the campaign for his party's poor result at the last election. However, he has not ruled out putting himself forward as party leader again one day.
Mr Slater said he first heard about the defamation claim this afternoon, adding he had not been served court papers.
He said he had two words for Mr Craig: "Bring it."
Mr Slater said he had "not one single concern" about Mr Craig's legal action because he was capable of funding his defence and he had evidence for everything he published about Mr Craig on his website.
"New Zealand can find out once and for all what a ratbag Colin Craig is," he said.
Mr Slater said if someone was going to stand for Parliament, it was important that the public knew about their background, especially if it contrasted with their Christian values.
Asked about Mr Craig's allegations of "dirty politics", Mr Slater said: "A: So what? B: Politics is dirty full-stop and if he doesn't like it then perhaps he shouldn't play away."
Mr Stringer, a former Conservative Party board member and candidate who is based in Christchurch, said this afternoon that he stood by everything he had said about Mr Craig.
He said he had never met Slater or Williams, though he had corresponded with Slater since Mr Craig resigned.
"There is no dirty politics campaign against Colin Craig," he said. "I've certainly not been part of one."
Mr Stringer has been critical of Mr Craig within the Conservatives and attempted to have the former leader's membership cancelled by an interim board.
He assumed the role of party chairman after the mass resignation of board members last month, but was told by other party members that he had been suspended for breaching the party's code of conduct.