Mr Stevens has resigned the infrastructure portfolio, from council's tenders board, the wastewater treatment plant legal review team, and the regional disaster fund. He has also relinquished his role as deputy chairman of Horizons regional land transport committee and his seat on the Manawatu-Wanganui Civil Defence emergency management group.
He has resigned as council rep on the Wanganui Events Trust but is expected to retain his seat as an individual.
"I'll be a councillor of nothing effectively. I'm meant to be the portfolio holder for infrastructure but I've had no terms of reference and I've no idea what I'm meant to be doing."
Mr Stevens was not prepared to give the new system more time to settle in.
"If you want something on the agenda you have to go through the mayor. What's been created is the mayor as a czar with total power - if she says 'no' to an item going on the agenda, then that's it.
The new structure came into effect this month after councillors asked for a review of the committee system in July. The three main committees - operating and reporting; strategy and policy; and audit, risk and finance - were scrapped and councillors allocated specific "portfolios" as their key responsibility.
The council used to meet every six weeks after a round of committee meetings but now it meets on two consecutive days every four weeks. If a councillor wants an item put to a council meeting, they must first raise it with the portfolio holder, mayor Annette Main or chief executive Kevin Ross.
The new system will be reviewed next July.
At least two other councillors are unhappy with the new arrangement.
Rob Vinsen said there had been a "lack of research" into the benefits of the change.
He said there were already cracks showing, with the last council meeting taking two days and meetings not finishing until after 6.30pm.
"But worst of all, one person is given the power to decide what is on an agenda. With a committee structure senior councillors were consulted and chairmen's recommendation meetings were held."
Philippa Baker-Hogan was prepared to support the new structure, but with only one meeting under the new system and flaws emerging, she said she would be surprised if councillors still supported the changes.
"I will strongly consider any move to re-instate the committees, because we will lose the confidence of our community if we continue to do our business in the manner we have."
Ms Main said claims items don't get to agendas unless they go through her office first were incorrect. "Agenda items come primarily from the chief executive and senior managers and, as a major portfolio holder, Mr Stevens is expected to lead those items in his area of responsibility."