Ms MacGregor has not made any public comment since stepping down two days before the general election in September last year, apart from accusing the former party leader of being "manipulative".
In a statement released by her lawyers this afternoon, she said Mr Craig had breached the agreement they signed after a Human Rights Commission mediation.
"Despite Mr Craig's public comments I have been advised by my lawyers that I am still bound by the confidentiality agreement," she said.
She was therefore unable to correct the "clear factual inaccuracies" made at Mr Craig's news conference in Auckland this afternoon "without jeopardising my legal position".
Ms MacGregor said she was willing to correct those inaccuracies if Mr Craig agreed not to take legal action in relation to the confidentiality agreement.
"I am also willing to fully brief the Conservative Party board on Mr Craig's conduct, but, again this would require Mr Craig's consent," she said.
Mr Craig admitted at the press conference that he might have breached the agreement, but said "wild and inaccurate" speculation meant he wanted to "set the record straight".
He also admitted that some of his interactions with Ms MacGregor were "inappropriate", but rejected accusations of sexual harassment.
Mr Craig confirmed he had agreed to pay Ms MacGregor $16,000 for work she had done for the party, following her surprise resignation. He also agreed to lend her $20,000 to cover outstanding credit card bills. When Ms McGregor was unable to pay this money back, he and his wife agreed to forgive the loan.
Mr Craig said this payment had nothing to do with allegations of inappropriate conduct between him and Ms MacGregor.
With his wife Helen standing beside him, he told reporters: "Let me make it clear I have never sexually harassed anybody."
Mr Craig would not elaborate on the details of his inappropriate interactions with Ms MacGregor, but when pressed he said his wife had forgiven him. He would not confirm whether he had penned a poem sent to Ms MacGregor, saying he would not go into any detail about his actions.
Mr Craig said he had voluntarily stepped down from the Conservative Party's board and would only stand for re-election of there was strong "grass roots" support.
He also responded to criticism he received from within the party about an interview he did in a sauna with TV3's David Farrier, saying: "I have to accept that my view and approach to things might not be [typical]."
Mr Craig said he did not think he had done the wrong thing by being interviewed in the sauna but accepted some others did not agree.
The Conservative Party's board may attempt to block Colin Craig from running again for the leadership role.
Board member John Stringer today called for Mr Craig's party membership to be cancelled. In a statement, he said Mr Craig had "so prejudiced the interests of the party" that he should lose his membership status.
The board is meeting in Auckland on Saturday, and Mr Stringer will insist that Mr Craig's membership is on the agenda.
The Conservative Party's constitution says the leader is chosen by a board vote. Mr Craig would not be able to seek re-election if his membership was cancelled.
Mr Stringer, who has been Mr Craig's most outspoken critic, said that the board also had power to veto any nominations for the leadership.
Several members of the 10-person board, including Mr Stringer, Christine Rankin and Laurence Day, have expressed support for a change at the top.
Mr Craig did not give a reason for his resignation on Friday. However, Mrs Rankin has said one of the factors was the circumstances around the departure of Ms MacGregor.
Mr Stringer said Mr Craig's "misdemeanours" were a "church picnic" compared to the dismissal of former candidate Larry Baldock.
Mr Baldock was suspended earlier this year after breaching the party's policy on speaking to the media.
Mr Stringer said: "I believe in even-handedness consistent with our key policy plank 'One Law For All' which Colin has championed so publicly."
No one has yet put their hand up to replace Mr Craig. Mrs Rankin and former Napier candidate Garth McVicar have ruled out running for the leadership.
Craig speaking to lawyer
Earlier, Colin Craig said he has received hundreds of supportive messages from party members and will listen to them and not the board members who oppose him.
Mr Craig said he would consult lawyers today and send a formal warning to Mr Stringer over comments made about the party founder's conduct.
But Mr Stringer thumbed his nose at Mr Craig's legal threat, saying support among board members for the return of their leader had "vapourised" over the weekend.
"I have been talking to the board. Colin has zero support. He won't be [reinstated]," Mr Stringer told the New Zealand Herald.
Mr Craig's brother, Andrew Craig, is a board member. Mr Stringer said he could not speak for him, but "Andrew is very supportive of my position".
"I know that he along with other board members are very unhappy with Colin's behaviour."
Andrew Craig would not be drawn when asked if he would like to see his brother return as leader.
Another board member, Laurence Day, said he was not aware of any board member who wanted to see Mr Craig recalled as leader. "I don't see, at the board level, any great enthusiasm for him to return.
"You have to respect the guy for what he's done, but ... I can't speculate on the veracity of what's going around."
Mr Day and his wife, Katrina, gave $675,000 to the Conservatives' election campaign. He said he would still support the party.
National may benefit, PM believes
The strife enveloping the Conservative Party could benefit National, Prime Minister John Key says.
Board members opposing the return of Mr Craig as leader have said they believe the party can rebound under a new leader. There have been discussions about potential new leaders since before Christmas, board member John Stringer said, and there are interested candidates.
Mr Key said this morning it was not clear how strongly the party would emerge from its current difficulties.
The Conservatives achieved 3.97% of the vote in the 2014 general election - more than 95,000 votes, but short of the 5% needed to enter Parliament.
"You just don't know how all this stuff is going to play out. He has been the big funder of the party. We are two and a bit years from the election. It's a long way to go," Mr Key told the Paul Henry show.
"Those Conservative voters...if they [the party] were not so strong a voice - they have well come back to us."
- NZ Herald and NZME News Service
