The deputy leader of NI21 has said that if his troubled party was a cow "you'd be getting it put down".
John McCallister, who suggested he would soon be quitting the party, described NI21 as the "most toxic and poisonous experience of my entire life".
And the South Down MLA said he now regretted forming the party with Basil McCrea, his own party leader.
He said it made his experience in the Ulster Unionists – the party he quit to form NI21 – "look like a Sunday school outing".
"I think it's pretty obvious that I don't have a long-term future with NI21," he said. "They don't want me in the party and I don't want to be in the party for much longer."
Mr McCallister had initiated an investigation into allegations of inappropriate sexual behaviour made against Mr McCrea – which the party leader strongly denies.
Last night, a party council candidate quit NI21, describing it as a "soap opera".
Mr McCallister said the party halted the investigation by mediation firm Carecall into the allegations against Mr McCrea because party chairperson Jane Howson would not give her permission for it to continue.
But on Monday the party executive directly contradicted this – and threatened to discipline Mr McCallister.
Asked if he thought he had a future with the party, he replied: "After statements like that – probably not."
Mr McCallister said last night he had yet to be contacted about any action but the media would probably hear about it first.
In a hard-hitting statement, the NI21 executive had said legal advice it had received made it clear that approaching Carecall to investigate the matter was wholly inappropriate.
It added that Mr McCallister ignored that advice, and went on to criticise the "wholly inappropriate and unprofessional way" in which details of the process had been leaked to the media.
Mr McCallister described the NI21 executive statement as "bizarre", as it had criticised him for going to the media yet did the same thing itself.
"It seems a little disingenuous to say the least," he added. Mr McCallister said the executive could have addressed the issues privately "instead of coming out in a full-blown statement without giving me any opportunity to respond to any of these points".
Mr McCallister told the Slugger O'Toole website it had been the "most toxic and poisonous experience of my entire life".
He said: "The last seven weeks have been awful in trying to manage and set up a process and trying to persuade colleagues in the old executive and in the new executive that we have issues that we need to address here.
"If Basil is exonerated, super – but we need to put in place a process to do that. We don't have the capacity within the party and we needed to bring in help from the outside."
And an NI21 candidate last night quit the party over the executive's statement.
David Honeyford, who stood unsuccessfully for the new Lisburn/Castlereagh super council, said: "The statement to the media by the new executive was the final straw for me.
"As a member and candidate I have been kept completely in the dark by the new party executive.
"Yet I read a pathetic, naive public statement that simply enraged the situation and widened the soap opera plot. I have no confidence in the party leadership or the party executive."