The outgoing Director-General of Health, Stephen McKernan, says he is not being pushed from his job.
Mr McKernan has been in the role since 2006 and his term of appointment expires at the end of July, but he said yesterday he would not be seeking re-appointment
Labour's state services spokesman Grant Robertson suggested Mr McKernan might have been forced out, through the Government's decisions on the recently announced National Health Board.
"Stephen McKernan's decision not to seek re-appointment begs the question. Was he pushed or did he jump?" asked Mr Robertson.
But Mr McKernan said he was leaving of his own accord.
Asked by TV3 whether he was pushed: Mr McKernan said: "The decision to go is mine."
Mr McKernan earlier issued a statement saying he had thoroughly enjoyed his time in the different roles he had undertaken.
"The health and disability sector is an incredibly rewarding, but also very challenging work environment. I consider myself privileged to have worked with so many talented, professional and dedicated people that serve New Zealanders so well."
He said he was proud of the health system, which he described as "world class in many areas".
His career in health includes more than 20 years in senior health management positions, including the last 12 in chief executive roles.
Mr McKernan said he was discussing a number of options and would make an announcement about his future in due course.
CTU president Helen Kelly said he was a great loss to the ministry as he had built strong relations with the sector and the ministry was going through major change.
Association of Salaried Medical Specialists executive director Ian Powell hoped that Mr McKernan had not been forced out of the job.
"Otherwise it will send an intimidating message to his successor, other health ministry officials, and district health board leaders to tailor their advice to what they think their political masters want to hear," Mr Powell said.
Other sector organisations also praised the outgoing health boss and voiced concerns about his departure.
Mr McKernan said his five months notice would allow for a replacement to be found and for him to manage the changes at the ministry.
He could not rule out redundancies, but Mr McKernan said he supported the changes being made.
Health Minister Tony Ryall said he hoped Mr McKernan would remain in the health sector.