Michael DiRienzo has resigned as Hunter New England Health chief executive.
Health district staff were advised of the development on Monday afternoon.
Mr DiRienzo, who has been on annual leave since late December, will leave his position on March 9.
"We wish to acknowledge and thank Michael for his years of contribution and achievement as chief executive of the district," a statement said.
NSW Health Pathology chief executive Tracey McCosker has been appointed as acting chief executive while a recruitment process takes place.
The Newcastle Herald reported on December 23 that a mediator was working to resolve tensions within the health district, in particular between the executive team and Mr DiRienzo.
The health district said at the time that Mr DiRienzo would take six weeks of annual leave.
Hunter New England Health's leadership team consists of 15 executives, including chief executive Mr DiRienzo. Executive director of medical services Professor Trish Davidson AM and the John Hunter Hospital's executive general manager Leanne Johnson both announced late last year that they would be leaving their roles in January.
The Herald understands part of the mediator's role was to facilitate discussions between Mr DiRienzo and John Hunter Hospital doctors, after 93 per cent of 162 surgeons, anaesthetists, obstetricians and gynaecologists polled in last October voted "no confidence" in Hunter New England Health's senior management.
The poll also found that 82 per cent of surgeons had been directed to change patients' clinical urgency categories to meet NSW Health's elective surgery benchmarks, prompting an audit to investigate the claims.
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