Scott Morrison's decision to elevate his former chief of staff Phil Gaetjens to head the public service "paints a picture" Labor is worried about - but the Opposition says it will give the new appointee a chance.
Labor's public service spokeswoman Katy Gallagher said it remained to be seen whether the outgoing Treasury chief would protect the federal bureaucracy's independence as Prime Minister's Department secretary.
Senator Gallagher accused the Prime Minister of arrogance in his handling of the public service after he commented on Thursday about his expectations for the bureaucracy.
"The Prime Minister has got to be the one that makes sure the public service isn't politicised and isn't diminished in the job that it does in the next three years," she said.
Labor was restrained in its comments about Mr Gaetjens, who previously drew the open hostility of its MPs and faced an exit from Treasury had the Opposition won the May election.
"We're being quite fair in saying let's see how Mr Gaetjens goes," Ms Gallagher said.
She called on the Coalition to release the Thodey review into the public service when it was ready, saying that Mr Morrison had not outlined how he would pursue the changes he wanted for the bureaucracy.
"We know that this government is seeking about $5 billion in savings from the public service in the medium term so we know that there is a lot of upheaval ahead," she said.
"From our point of view we want to ensure that the institution itself is there, it's independent, it's there to serve in the national interest and the Prime Minister has to ensure that occurs."
Mr Morrison's pledge for reform drew more fire from Greens public service spokesman Adam Bandt, who said the Prime Minister's words foreshadowed an attack on the bureaucracy.
"The erosion of the public service has been steadily occurring under the old parties, through privatisation by stealth and relentless outsourcing," he said.
"Now, emboldened by the election, the government looks to be preparing for a direct attack."
Mr Gaetjens will replace Martin Parkinson as secretary of the Department of Prime Minister and Cabinet in September.
Mr Morrison announced Dr Parkinson's retirement after a lengthy and respected career in the Australian public service, including the top mandarin's role and as Treasury secretary.
The news broke on Thursday morning as the Prime Minister summed up his views of the bureaucracy to News Corp as "respect and expect".
"We don't expect the public service to run the government. That's what we were elected to do," he said.
"In my experience, the public service always works best when it has strong guidance and leadership."
Mr Gaetjens said leading Treasury had been a privilege and his appointment to lead the bureaucracy reflected well on his staff.
His appointment to the top bureaucratic role was met with reservation in some quarters given his history as a Coalition political staffer to then-treasurer Peter Costello.
Mr Morrison said Infrastructure secretary Steven Kennedy would be elevated to the Treasury secretary role.
"[Mr Gaetjens] has been more closely involved in central agency planning and budget than most people in this town, at all levels," the Prime Minister said.
"Again, at state and federal level. How we work with state governments is absolutely critical to my agenda. As you know, I have worked closely with Phil in the past, and I am looking forward to working closely with him again, and I am looking forward to what he will bring to the delivery of the government's agenda, and ensuring it is well understood across the public service, and that we are getting on with the job of delivering on that agenda."
Mr Morrison noted Mr Gaetjens had previously worked for the Coalition politically, but said it was not uncommon.
"This is about merit, this is about people that know how to get a job done, and people have earned the respect for the roles that I think they will now be able to serve in," he said.
When asked whether appointing a former Coalition staffer to the nation's top public service job would be seen as politicisation of the bureaucracy, Mr Morrison listed former Labor appointments to the APS.
"From Don Russell to Tim Lee, Geoff Ferry, Richard Mort. This is not uncommon that people have worked in the political sphere and the bureaucratic sphere, because it is both, and where they have that experience, I think that aids them well in the tasks that they have," he said.
"In the secretaries that I currently have working under the Coalition government, Rosemary Huxtable, Steven Kennedy, Daryl Quinlivan, Frances Adamson, all of them have served in both political roles for Labor and are doing an outstanding job for me in the secretary roles they have.
"It is about merit and it is about quality. And in the two appointments I have announced today, I believe that the two men have done an extraordinary job, and have earned my trust and my respect and the respect of my government."
Mr Morrison thanked Dr Parkinson for a "distinguished career in the public service".
"Martin has been a highly valued source of advice to me, both as Prime Minister and in other portfolios, and he has led the Australian Public Service with great distinction," he said.
"His policy acumen across a range of domestic and international policy areas has helped Australia navigate a complex and rapidly changing world.
"I wish him well for the next phase of his career and I look forward to him serving the national interest in other capacities."
Mr Morrison's comments come as the nation awaits the final report of the Thodey review, initially begun by then-prime minister Malcolm Turnbull. It was a key issue Dr Parkinson had pushed for in the top job.
The review will spearhead an expected overhaul of the public service with what Mr Morrison alluded to would be a more "public-facing" public service, focused on implementation, though it was unclear what the Prime Minister's long-term intentions were for the service's policy advice role.
While the Thodey review is still yet to be released, the draft report forecast proposals for a long-term move to more homogenised workplace agreement or agreements across the public service, and proposed efforts to break down the siloed arrangements of departments.