TV show The Project broadcast footage this week of the former agriculture minister bragging about how he got the best out of public servants in Canberra.

However, his account conflicted with other versions of why the department's then secretary, Paul Grimes, lost in job in March 2015.

In The Project's footage, filmed at a community forum in February this year, Mr Joyce told his audience how he had wrested power from "the bureaucrats".

"... I found out one of the only ways I could deal with them when I was [agriculture] minister was I invited the head of the department up, brought him into my office and sacked him, just to remind him where the authority starts from," Mr Joyce said. "Then I got a lot more sense out of the rest of them. They were great."

Dr Grimes, a former head of the ACT Treasury before he moved to the federal bureaucracy, is now Victoria's Public Sector Commissioner.

He declined to comment on Tuesday when asked about Mr Joyce's comments.

However, other reasons for the pair's falling-out have been canvassed publicly since Dr Grimes was sacked.

The souring relationship first became obvious in October 2014, when Mr Joyce's advisers sought to change a parliamentary transcript to remove errors about the amount of drought aid the government had given to farmers.

Dr Grimes and the minister's office clashed over whether to make information about the changes public. The disagreement deepened, and the secretary later wrote to Mr Joyce that he "no longer has confidence in my capacity to resolve matters relating to integrity with you".

Two-and-a-half years ago, Mr Joyce offered a different reason for why he and Dr Grimes couldn't work together.

"It's quite obvious that the relationship had fallen into basically a point of no return," he told a rural newspaper in 2016.

"It was a time of high pressure, we were doing the agriculture white paper, the negotiations were tense."

Mr Joyce eventually asked the Department of the Prime Minister and Cabinet's then secretary, Michael Thawley, to intervene. Mr Thawley concluded "a relationship of strong mutual confidence" between Dr Grimes and Mr Joyce "was not a realistic prospect".

On the advice of then prime minister Tony Abbott, Governor-General Sir Peter Cosgrove sacked Dr Grimes in March 2015, making him the fourth department head dismissed under Mr Abbott.