Gaurav Sharma has officially been expelled from Labour after bringing "the party into disrepute", party president Claire Szabó said.
It comes just days after Sharma announced his resignation from Parliament, claiming Labour was ready to force him out. Labour has rejected that claim.
He was kicked out of the Labour caucus in August after making unfounded allegations of bullying towards MPs. He was then referred to Labour's governing body the New Zealand Council to decide whether he should be expelled from the wider party.
The New Zealand Council met on Thursday morning after an investigation which Labour said Sharma participated in.
"Labour's New Zealand Council has expelled Gaurav Sharma from the party," Szabó said. "The Council took this decision because it found Gaurav Sharma had brought the party into disrepute."
His expulsion is effective immediately, Labour said.
Sharma, who became an independent MP after being booted from the Labour caucus, announced his resignation from Parliament on Tuesday.
He claimed Labour was planning to use waka-jumping legislation to force him out of Parliament ahead of next year's general election. If he left Parliament within six months of the election, politicians could choose not to hold a by-election.
Sharma was concerned this would leave his Hamilton West constituents without a MP for months. By resigning this week, he triggered a by-election which he will run in.
However, Labour leader Jacinda Ardern said there was no plan to use the waka-jumping legislation and has no idea what led Sharma to believe that. She said he should reconsider his decision as a by-election would cost hundreds of thousands of dollars.
Ardern said on Wednesday that no decision had been made on when to hold the by-election as she is still waiting on advice from the Electoral Commission.
But the Prime Minister is already downplaying Labour's chances in Hamilton West. She said her party has been an "underdog" there lately.
"In recent elections, we've held it once out of five. That is the history of this seat. I let that record speak for itself for the type of contest it is likely to be," she said.
When it was pointed out by Newshub that the electorate usually goes to the largest party - wasn't between 2008 and 2020 - Ardern said there have been boundary changes.
"I am saying that in recent times we have been the underdog in that seat. I do think it would be a very robust and tough by-election," she said.
Newshub revealed on Wednesday that Roshan Nauhria, a wealthy businessman, is willing to back Sharma's by-election campaign.
"I will support him financially, 100 percent. Wholeheartedly… [it] doesn't matter the money, whatever he needs."
Sharma was kicked out of Labour's caucus in August after making claims of bulllying, accusing the Prime Minister of conducting a cover-up and the party of teaching politicians how to get around freedom of information laws.
Dr Sharma hasn't provided any evidence of being bullied or that there are widespread workplace culture issues. The MP has, however, released recordings and screenshots of private conversations he believes shows he has support within the caucus.
Labour's denied his allegations, saying the situation has arisen from Dr Sharma taking issue with interventions from the Parliamentary Service and whips to resolve staffing issues in his office.
