Prime Minister Malcolm Turnbull may have to call in Finance Department secretary Jane Halton or another public service boss to help choose replacements for key positions at the top of the federal bureaucracy.
Three department head positions have become available at Communications and the Arts, Education and Training and Foreign Affairs and Trade.
Section 58 of the Public Service Act requires three key people to make the decision about who will fill these positions - Mr Turnbull, the Australian Public Service Commissioner John Lloyd and one other.
The last person is the Department of the Prime Minister and Cabinet secretary which, depending on whether decisions are made before or after January 23, could be the outgoing Michael Thawley or the incoming Martin Parkinson.
The PM&C boss, whoever it is, will effectively work on a report with Mr Lloyd to be handed to the prime minister.
Because of the reshuffle it is not clear who precisely will have discussions with the public service commissioner.
The first option is that Mr Thawley has input into who fills these jobs, even though he is about to leave the public service.
The second option is that decisions are delayed until Dr Parkinson takes the helm but this poses another problem. His wife, Dr Heather Smith, is a PM&C deputy secretary and contender for one of the jobs up for grabs.
She could apply for any of the three jobs available.
Public service observers had no doubt Dr Parkinson would distance himself from any process involving his wife. But how would the process work if this happened?
Professor John Wanna from the Crawford School of Public Policy and other sources said they could see another experienced secretary being brought in to stand in Dr Parkinson's place during the decision-making process.
Professor Wanna said this would be a central agency boss such as Ms Halton, the longest-serving department secretary in the bureaucracy at the moment, or Treasury secretary John Fraser.
One source said Dr Parkinson may be given the option to choose who his replacement in this process would be.
It was unlikely he would want to leave it solely to Public Service Commissioner Mr Lloyd to advise the prime minister.
Also at play was when decisions needed to be made.
The Communications and the Arts job is vacant now but there is probably no urgency to find a replacement before the end of the year. The Education and Training secretary position will be vacant by February and the government has until July to fill the job of DFAT boss.
Choosing people to fill these jobs might be a combination of Mr Thawley and Dr Parkinson being part of the process at different times - with the latter excusing himself from discussions at key times - with another secretary brought in along the way as well.
Professor Wanna said public servants played a major role during this process because the prime minister often had little idea about the strengths of bureaucrats rising through the ranks.
"They're trying to pick people [for these jobs] who are competent and easy to work with," he said.
Unofficially influencing the decision will be other public service secretaries who regularly put forward their opinions about rising talent to the public service commissioner.
Finally, Mr Turnbull's chief of staff, former Communications Department secretary Drew Clarke, will have a key role.
He recently held one of the jobs needing to be filled and already knew of some of the best minds sprinkled throughout the bureaucracy.
Once the final selections are made the governor-general goes through the usual formalities of approving.