Lucy Schwaner has dramatically quit the Howick Local Board less than a month after the election.
Schwaner said in a statement to the Herald that she had resigned because she had no confidence in the chairmanship of David Collings.
Apart from thanking her supporters, Schwaner said her only further comment was restricted to the letter she sent to board members on Sunday, seeking the chairmanship, and her resignation letter.
She supplied both to the Herald.
In her resignation letter, she alleged board had become a "toxic environment".
She also claimed a culture had developed of attacking council employees, but given a majority of board members decided to continue Collings' leadership, she had to resign.
Collings told the Herald last night Schwaner had walked out after the board voted 5-4 in favour of him holding the chairmanship for a second term.
The task was the board's first after members were sworn in at the start of the meeting.
Less than half an hour after walking out, Schwaner tendered her resignation.
Her decision was "disappointing", and a surprise as they had both stood on the Vision and Voice ticket, Collings said.
In response to her allegations, he said: "I'm not going to lower myself to that level. I've got the support of the community and I've got support from the board."
He had not encouraged a culture of attacking council employees, and Schwaner had not shared any concerns with him before her resignation, he said.
He did not know if a by-election would be needed, or if the next highest candidate would now be elected.
He also did not know how much a by-election would cost, but he had heard it could be as much as $70,000.