Labor senator Katy Gallagher has accused Department of Prime Minister and Cabinet secretary Phil Gaetjens of being Scott Morrison's "butler", cooking up political fixes "when the bell rings".
The ACT parliamentarian launched the extraordinary attack on Canberra's top bureaucrat, after Mr Gaetjens absolved embattled Nationals Senator Bridget McKenzie of pork barrelling with a $100 million community sports grant program.
His advice to the Prime Minister was at odds with the findings of the Australian National Audit office, which uncovered evidence Senator McKenzie's office used to fund to target seats the Coalition wanted to win at the 2019 election.
However it will not be released publicly, as it is classified as a cabinet document.
Senator Gallagher said Mr Gaetjens - whose earlier appointment as Treasury head Labor had opposed because he worked for three years as Mr Morrison's chief-of-staff - had the chance to prove them wrong and uphold the independence of his office through this report.
"Instead, the secretary dished up a report that gave the Prime Minister exactly what he was after - political cover for himself, while also providing a basis to sack the minister," Senator Gallagher said.
Senator Gallagher suggested Mr Morrison had either misrepresented Mr Gaetjens' report, or the secretary had given him advice "engineered for political expediency".
Referencing a newspaper report which said Mr Gaetjens could read Mr Morrison's mind, Senator Gallagher said the Prime Minister did not even need to ask his secretary for a "political fix".
"The only way for the Prime Minister to reassure us of Mr Gaetjens' suitability for his current role is to release the McKenzie report immediately. Otherwise, this question will follow Mr Gaetjens throughout his tenure," Senator Gallagher said.
"Is he the head of the Australian public service? Or is he Mr Morrison's chief servant? Is Mr Gaetjens is responsible for ensuring the Australian government gets the advice it needs to make decisions ... in the interests of the Australian people? Or is he Mr Morrison's head butler, serving up cooked-up political fixes when the bell rings?"
However Liberal senator Zed Seselja described Senator Gallagher's comments as a "grubby, disgusting attack on a senior and distinguished Australian public servant".
He accused her of gunning for Mr Gaetjens, because he was on Labor's "hit-list" had it won the election.
Mr Gaetjens has previously rejected allegations of bias due to his former job.
Senator Seselja also said the grants program had funded "critical" projects for the Woden Valley Gymnastics club, the Brumbies and the Canberra Netball Association.
"Frankly, the ACT government, if it were doing a better job would have invested in [these projects] by now but of course we've had to come in through our superior economic management and invest in these critical community facilities," Senator Seselja said.
Over in the House of Representatives, Mr Morrison - facing his first Question Time since the controversy emerged - tried to claim Senator McKenzie had "total authority" to make decisions under the program.
In fact, Auditor-General Grant Hehir found "there was no legal authority evident to the [audit office] under which the minister was able to be the approver of Community Sport Infrastructure Program grants".
The audit "the program was set up that gave total authority to the minister, to make decisions," Mr Morrison said, and the audit "articulated that the authority to make those decisions was by the minister".
"Ministers must make decisions," he said. "If those opposite think that ministers should be order takers from public officials, that's for them to say."
The Australian parliament also could hear from a long list of clubs who missed out under the controversial Community Sport Infrastructure Grant program as the Morrison government remains under fire due to the scheme.
Senator McKenzie's resignation on Sunday did little to alleviate the pressure building on the government over her apparent use of the community sports grants program to sandbag Coalition electorate and target key Labor seats.
Labor gained crossbench support to set up an inquiry into the use of the scheme.
The Senate also passed a motion ordering the government to table documents related to the scheme, including the Gaetjens report.
Leader Anthony Albanese said on Wednesday the inquiry could not only call the Auditor-General to give evidence, but also many of the clubs that failed to get a grant.
"Well, obviously, a place to start will be the Auditor-General. The dismissal by the government of the Auditor-General's report, that is very clear, in favour of a report by Scott Morrison's former chief of staff, who says, 'nothing to see here', and Scott Morrison's Attorney General, is quite frankly, farcical. And that is a good place to start," Mr Albanese said.
"I think another place to start will be, once the list is available of all of the clubs, to actually hear from some of the clubs about how it is that their applications were overlooked. We might actually have some witnesses might choose to try to come forward and ask to speak about the need for a National Integrity Commission so that these sorts of rorts can't happen into the future."
Earlier, Labor tried and failed to get a motion up in the lower house to force the government to give grants to clubs that missed out under the program.
However both Prime Minister Scott Morrison and Deputy Prime Minister Michael McCormack have signalled there may be a future round of sporting grants after the scandal came to light.
- with Kirsten Lawson