Canberra's most senior public servant is set to break his silence about his controversial report on Bridget McKenzie's sports rorts, as the Morrison government defies a Senate order to release the document.
Department of Prime Minster and Cabinet secretary Phil Gaetjens has been under fire after his report on Senator McKenzie apparently absolved her of pork-barrelling.
Mr Gaetjens - who is Prime Minister Scott Morrison's former chief of staff - did find Senator McKenzie breached ministerial standards by giving grants to gun clubs she was an undisclosed member of.
While this triggered her resignation, Mr Gaetjens also reportedly disputed the finding of the Australian National Audit Office, which found a "distribution bias" in the way the minister's office was doling out community sporting grants. His report has not been released.
In a letter on Thursday, Senate Leader Mathias Cormann claimed public interest immunity over the report as it was the subject of Cabinet deliberations.
"As is well recognised in the Westminster system, it is in the public interest to preserve the confidentiality of cabinet deliberations to ensure the best possible decisions are made following thorough consideration and discussion of relevant proposals within cabinet," Senator Cormann wrote.
"Disclosure of the document subject to the motion is not in the public interest as it would reveal cabinet deliberations."
However Senator Cormann said Mr Gaetjens had advised the Prime Minister that he "intends to make a public statement in due course".
Mr Gaetjens has been personally criticised for his finding that Senator McKenzie acted within the remit of her ministerial discretion when using an electorate-based, colour-coded spreadsheet to determine where grant funding went.
Former Department of Prime Minister and Cabinet secretary Dr Michael Keating said the Gaetjens report "reflects poorly on its author".
ACT Labor senator Katy Gallagher accused Mr Gaetjens of being Mr Morrison's "butler", cooking up political fixes "when the bell rings".
A spokesperson for Prime Minster and Cabinet has previously denied any allegations of bias.
"Mr Gaetjens is a long-standing public servant who has served, and continues to serve, the government of the day impartially and professionally," the spokesperson said.
"Like many senior public servants, his career has included periods working for ministers."
Prime Minster and Cabinet has been contacted for further comment.
Mr Gaetjens could also be hauled before a Senate inquiry into the sports rorts saga, which was set up this week.
Meanwhile the Coalition is now under scrutiny over a separate sport grants program.
Mr Morrison announced $150 million would be spent supporting the development of female change room facilities at sporting grounds and community swimming facilities across Australia through a new dedicated stream of funding seven weeks out from the 2019 election.
However the ABC reports most funding went to swimming pools in just 11 Coalition-held electorates. Projects were also selected without the recipients having applied or even being aware they were under consideration.
Greens senator Larissa Waters has asked the Auditor-General to look into this program as well.
"Memo to the government - you can't use public money to buy election outcomes! It's called rorting and it's a corruption of democracy," Senator Waters said.
Senator Waters will also try to force a vote on her integrity commission legislation in the House of Representatives next week. The bill passed in the Senate last year.
The Greens' model of corruption watchdog is stronger than that originally proposed by the Coalition. Attorney-General Christian Porter failed to release the government's integrity commission legislation by the end of last year as promised.