Carter threatened to reveal private details - Little

Former Labour MP Chris Carter threatened to disclose the private information of other Labour MPs if expelled from the party, party president Andrew Little says.

Mr Carter, the MP for Te Atatu, was expelled from the party last night during a seven-hour meeting of the party's national council in Wellington.

The council found he had breached rules by acting in a misleading manner likely to cause internal discontent and encourage external ridicule.

He had already been thrown out of the party's parliamentary wing after sending an anonymous letter to the media in July, which said a coup was planned against leader Phil Goff because he couldn't win the next election. He was quickly outed as the letter's author.

Mr Carter this morning told Radio New Zealand his expulsion was an overreaction and the party leadership has been "petty."

"I just think it's a ridiculous over reaction to make Phil Goff look strong."

Mr Carter said the party had been unprofessional and petty in its handling of the situation. "Nothing I put in my letter was incorrect, the way I did it was ridiculous, stupid."

However, he said he would not do it again. He plans to serve the rest of his term as MP for Te Atatu and said he would decide next week whether to appeal the expulsion decision.

However, Mr Little told NZPA that Mr Carter was the only person who did not understand that what he had done was wrong.

Mr Carter did not accept that writing an anonymous note to the Parliamentary press gallery, blaming others for it and not owning up when confronted had the potential to cause considerable damage to caucus for many months, Mr Little said.

"And he's continued the attack on Phil Goff ... ultimately that's an attack on the party and he doesn't accept that, he thinks that it's OK.

"It is Chris who doesn't understand the magnitude of his actions."

During the meeting last night Mr Carter threatened to disclose private information about unnamed Labour MPs if he was expelled, Mr Little said.

"He just said he had a lot of information on a lot of individuals in the caucus and that he wouldn't hesitate to disclose that if it suited him to do so," Mr Little told NZPA.

"That threat was clear but we couldn't be persuaded by that threat. It's not a very persuasive argument."

Mr Little said the party had treated the matter with considerable seriousness and gravity and there was reluctance to expel Mr Carter because of his history with the Labour Party.

Mr Little said he was confident that the whole process would stand up to close scrutiny but it was no surprise Mr Carter was threatening an appeal.

There was a "real possibility" Mr Carter would resign from his Te Atatu seat before the next election and Labour was ready for that, Mr Little said.