Chris Carter will be a lonely MP from now until the next election.

Although he says he will consider himself still a Labour member, that isn't the way the party or Parliament will treat him.

He has been thrown out of caucus on a unanimous vote and on August 7 the party council will almost certainly expel him.

That cuts him loose, and Parliament's managers will find a seat for him in the wilderness of the cross-benches.

The unsigned letter he sent to media representatives yesterday, seeking to undermine party leader Phil Goff and foment a coup against him, has ended the Te Atatu MP's career.

"I wanted it to be a snowball that started an avalanche," he said last night, claiming there were others in caucus who felt as he did -- that Labour couldn't win next year's election with Mr Goff at the helm.

If there were any others they didn't show themselves when Mr Goff called an urgent meeting of his MPs and moved to eject Mr Carter.

Mr Goff described Mr Carter's actions as stupid and disloyal.

"They were calculated to damage the party and the leadership. That is unacceptable to me and my caucus," Mr Goff said.

"There are no more chances...this was an action of an individual on his own, he has no support and no sympathy from the Labour caucus."

Mr Carter was insisting last night that he believed he had acted in the best interests of the party.

"I think I owe it to the people I represent and the people who voted for our party that we have a leader who can win the election," he said.

Mr Carter hasn't directly endorsed a challenger for the party leadership, although his letter said finance spokesman David Cunliffe "has a big smile on his face".

Mr Cunliffe told reporters he supported Mr Goff "100 percent" and would not challenge him.

Mr Carter's bizarre behaviour is the latest in a string of misadventures which have embarrassed Labour and tested Mr Goff's patience.

Earlier this year, when his spending as a minister in the previous government was first questioned, he accused the media of attacking him because he was gay.

Mr Goff was forced to say he didn't believe that was the case.

When details of all ministerial credit card spending were released, he again suggested he was a victim and at first attempted to justify his extravagance.

Ordered to apologise by Mr Goff, he led reporters on a chase through the corridors of Parliament and called a press conference the next day to say he was sorry about the way he had spent taxpayer money.

Because he holds an electorate seat, there is no way Labour can get him out of Parliament.

"The people who voted for me to serve them and I will be serving them until the next election," he said.

"I will be there as a Labour MP. If my Labour title has been officially removed from me, it will still stay with me."

It won't. He will be an independent MP and if he decides to contest Te Atatu in next year's election he will be up against a Labour candidate.