"Our current chief executive has proven to be very capable and competent in the role and has contributed greatly to the growth and management of Tauranga City.
"This decision is not a reflection on his performance.
"As a council, we have a lot of major projects under way and elected members believe it is important that we have the certainty that a full appointment process and five-year contract would give."
Mr Brownless said the option of a shorter term was not desirable, "as the timing would have meant an appointment process taking place during the next local body elections".
A recruitment company would be engaged to support councillors, who would appoint the successful candidate.
"We will be running a robust process and we are confident there will be a lot of high-quality applicants to ensure we have the best possible person for the job," Mr Brownless said.
"While this process is undertaken, Garry has our complete support to carry out his duties."
Mr Poole was appointed chief executive in April 2013 and said he was focused on continuing the council's positive momentum.
"I am really proud of the work we have done over the past five years and I'm excited by the potential for Tauranga City Council looking forward.
"We have some important matters in front of council at the moment and it is great to have the mandate of councillors to continue pushing ahead with these initiatives."
Mr Poole was previously chief executive of Wellington City Council for 15 years.