"However the cost to the community is far greater if the Howick local board were allowed to continue unchecked and without its deep problems or poor leadership highlighted for the public.
"Leaving the board was the most honourable course of action given I have no confidence in the leadership of David Collings."
Schwaner said the cost of the by-election could be avoided if the next-highest ranked unsuccessful candidate Mike Turinsky was to run unopposed.
In her resignation letter Schwaner alleged that under the chairmanship of Collings in the past term the board had become a "toxic environment".
At the time Collings said Schwaner's decision was "disappointing" and a surprise given they both stood on the Vision and Voice ticket.