Wairarapa DHB chief executive Tracey Adamson will step aside next year after more than 3 years in the job.
Ms Adamson has confirmed she will not apply for the new joint chief executive role for Wairarapa and Hutt Valley's DHBs.
While seen as one of the forerunners for the new position, announced last month, she said she would not apply for personal reasons.
Ms Adamson said she had decided to explore other opportunities, and was due to finish work in January 2013.
Wairarapa DHB Bob Francis paid tribute to Ms Adamson and thanked her for doing a "wonderful" job, and praised her dedication and achievements as chief executive.
"Since her arrival in April 2009, Tracey has led a significant programme of change and quality improvement in Wairarapa DHB," Mr Francis said.
"She built a strong team that has effectively implemented our strategy of working closer with our neighbouring DHBs, both locally and regionally."
On October 18 Wairarapa DHB and Hutt Valley DHB announced their senior management teams would merge, starting with the chief executive position, as moves to share services between Wairarapa, Hutt Valley and Capital and Coast DHBs continued.
Speaking then, Mr Francis said, "It was what can we do in one go without turning the three DHBs upside down and continue operating."
Ms Adamson said despite her decision to step down she remained fully committed to the changes being formulated for the DHB. She added that she would spend her remaining months working with staff and neighbouring DHBs to maximise the exciting opportunities which the changes would bring.
"Wairarapa has valuable experience to offer our neighbours. Our track record in managing services efficiently and meeting our health targets is enviable," Ms Adamson said.
She would leave the organisation secure in the knowledge that future developments had clear clinical leadership, were improving the experience for patients and were improving health.
Mr Francis said the process of appointing a new joint chief executive was under way and expected an appointment before Christmas.