Labour MP Charles Chauvel is thought to be one of the three members of Parliament Chris Carter claims he plotted with about a leadership change on the night before he sent an anonymous letter to media.
Mr Chauvel denied plotting against Labour leader Phil Goff but said he could have been in Mr Carter's office on July 28 - the night on which Mr Carter claimed he met with three other Labour MPs to discuss the best time for a leadership change.
Mr Carter sent his anonymous letter to the Parliamentary press gallery the next day, claiming a leadership challenge would take place before the next election.
Mr Chauvel said that while he could not recall that night, he was often in Mr Carter's office. He rejected any claims they had discussed a leadership change.
"Chris is either confused or imagining discussions that didn't occur. I've never been involved in any plotting or scheming against our leader and although I'm a good friend of Chris - and hope to remain so - I've certainly never engaged in any discussions calculated to undermine our leadership, which I fully support."
On Monday, Labour's ruling council expelled Mr Carter for undermining the party by his actions.
His submission to the disciplinary meeting in defence of his actions was leaked to media and included the July 28 meeting as well as a further claim that there were 17 Labour MPs with whom he had discussed a change of leadership.
The information was included to try to counter the charge that he was being dishonest when talking about dissent in the ranks.
Concern that Mr Carter will start to reveal names prompted much speculation within Labour about who the three MPs were.
Most of those mentioned in the speculation were quick to deny it.
Ruth Dyson "categorically" denied having any such discussion with Mr Carter.
She had been in his office only once since the election and that was to meet a health minister from overseas.
"I have not plotted against Phil Goff and/or [deputy party leader] Annette King. And I haven't talked to Chris about much at all actually, including leadership.
"He's hallucinating if he thinks I've ever had a discussion with him about anything."
Lianne Dalziel did not return calls and her staff said she was in a conference.
Shane Jones and David Cunliffe denied being among the three, as did Moana Mackey, whose name also arose in the speculation.
David Shearer and Phil Twyford both said they were not in Mr Carter's office that night. They were due to travel to the Solomons the next day.
Labour's council expelled Mr Carter after a marathon seven-hour session because of the damage he had done, the way he had sent the letters and his apparent lack of contrition.