Hutt City councillor David Bassett has resigned.
The move will trigger a byelection in Lower Hutt's Central Ward, which is expected to cost $50,000.
Bassett is an independent councillor and has been on council for almost 14 years, for nine of those years he was the city's deputy mayor.
But since Ray Wallace lost the mayoralty to current mayor Campbell Barry, Bassett has not been given positions of responsibility like being a committee chair.
In March he resigned from the role as Wellington Water Committee chairman after holding the position for eight years.
In a letter sent to committee members this week he said it was an appropriate time to stand down from the role due to the Government's Three Waters reforms being well underway.
Barry sincerely thanked Bassett for his years of service.
"Ultimately he has decided it is the right time for him and his family to step back from public life, and I am supportive of his decision."
Hutt City Council chief executive Jo Miller confirmed she received a letter of resignation from Bassett today, effective immediately.
Miller said nominations for the position will open on June 17 and close at 12pm on Thursday July 15.
If there was more than one nomination, an election will be required.
Voting will be done by a postal vote closing at 12pm on September 10, 2021.
Bassett has been approached for comment.