He began getting in touch with medical groups and individuals of all kinds and interests to talk about a whole range of issues that went well beyond protecting the country from exotic diseases, which for years had been the traditional focus of the nation's top medical adviser.

One of those he contacted was Bastian Seidel, who at the time had just been elected president of the Royal Australian College of General Practitioners.

"Pretty much right from the start he was reaching out to me as the incoming president of a GP organisation," Dr Seidel recalls. "At the time that was quite unusual because up to that point the CMO was mainly about infection control."

"It was very clear right from the beginning that he wanted to engage in all areas of health," he says.

Over the subsequent three and a half years Professor Murphy has made it his business to be involved in issues that span the health sector, from medical workforce planning and microbial resistance to opioid use and medical research.

He came to the role following an extensive career as a clinician and medical administrator.

Professor Murphy began as a specialist in nephrology (kidney health) but increasingly took an interest in management and administration, becoming chief medical officer for St Vincent's Health in Victoria and a fellow of the Australian Institute of Company Directors, and sitting on numerous boards including the Florey Institute of Neuroscience and Mental Health, the Olivia Newton-John Cancer Research Institute and the Victorian Comprehensive Cancer Centre.

His breadth of interest and expertise has made him an increasingly valuable source of advice for Health Minister Greg Hunt, so much so that few are surprised that he has now been annointed to succeed Glenys Beauchamp at Health Department secretary.

READ MORE: Brendan Murphy named Health Department secretary, replacing Glenys Beauchamp

In a shock move, Mr Hunt announced on Wednesday that Ms Beauchamp was retiring, effective February 28, and would go on leave from January 24.

Suspicions have been raised about the timing of Ms Beauchamp's departure because she has been a member of the Sports Australia Board that is at the centre of the sports grants furore which has engulfed the federal government.

But the government insists that there is no link, and a Health Department spokesperson said Ms Beauchamp's move was solely related to her 65th birthday.

"It is quite normal for a person to retire at that time, particularly after giving long and dedicated public service for over 30 years and to allow time for a seamless transition," the spokesperson said.

The timing of the change at the top of the Health Department has also been awkward for Professor Murphy, who is simultaneously embroiled in spearheading the nation's response the novel coronavirus outbreak, with four confirmed cases in Australia and three more under investigation as at late Sunday.

According to Chinese state media, the virus has so far killed 56 people in China, where there are currently 1985 confirmed and 2684 suspected infections. There are also cases in nine other countries including the United States, Japan, France, Thailand, Vietnam, South Korea, Singapore and Canada.

Professor Murphy has been giving virtually daily updates on the status of the outbreak and Australia's preparations and response, and AMA President Tony Bartone says clear and authoritative communication is one of the chief medical officer's strengths.

"We have times where we have not seen directly the same view but he is always responsive, engaged, conscientious," Dr Bartone says.

Dr Seidel clashed with Professor Murphy in 2018 over a letter sent out by the Health Department to thousands of GPs regarding opioid prescribing. Some described it as "intimidating".

At the time, Dr Seidel said that the letter risked unfairly targeting doctors who legitimately prescribed opioids for their patients, such as those in palliative care.

Professor Murphy eventually issued an apology for the anxiety and distress the letter had caused many GPs.

Dr Seidel said that, ironically enough, the episode highlighted the CMO's strengths as an administrator and operator.

"I disagreed with Brendan Murphy on that, but it was perfectly fine," he said. "If he is on the other side of the argument he is the person you want to have because he argues with logic and common sense and evidence. That is the exchange you want to have."

Dr Bartone said that, as the first clinician to be Health Department secretary (the previous medico to head health, Dr Gwyn Howells, held the title of director-general from 1973 to 1982), he would bring unique knowledge to the role.

"As a clinician, he basically brings an understanding of the art of medicine, which is something that many do not get," he said. "When you are able to bridge the clinical and bureaucratic worlds in one person it undoubtedly has to be a positive."