He said with all necessary groundwork to proceed with the scheme in place, the new group of councillors would soon make a final decision on the project, as well as setting a new direction to develop the council's strategic plan.
With two other senior members of the council's current executive team retiring in the coming months, Mr Newman said he felt it was timely to also consider his future.
"This is a decision I have given a lot of thought, especially over the summer break.
"I have decided to step aside to enable the new council to take whatever direction it sees as prudent with the support of a refreshed executive team," he said.