Tony Abbott has accused the nation's most senior public servant of being "out of line" over claims he damaged the public service by sacking senior bureaucrats after winning government.
Prime Minister and Cabinet boss Martin Parkinson said on Wednesday he held no personal animus towards Mr Abbott but removing departmental secretaries for following instructions of the former Rudd and Gillard governments had caused public servants to avoid controversial jobs.
Dr Parkinson was sacked as Treasury secretary by Mr Abbott, but returned to Canberra after being tapped to lead Malcolm Turnbull's department after his 2015 leadership challenge.
"You could have achieved the same outcome that he wanted to achieve far more subtly if people had stopped to think about it and without the damage I think it did to the public service because there were instances after that happened of senior colleagues reporting their staff saying, 'well I'm not going to put my hand up for a controversial role because this is what happens'," he told a Melbourne University interview.
"You follow on the democratically elected, legally mandated directions of the government of the day and you get sacked as a result."
Mr Abbott hit back on Twitter on Wednesday night, suggesting the comments were not impartial and were an inappropriate criticism of "a PM still serving in the Parliament".
"It's hardly the act of a politically impartial, professional public servant to claim that a PM still serving in the parliament has "damaged the public service"," he wrote.
"The PM&C secretary is out of line."
It's hardly the act of a politically impartial, professional public servant to claim that a PM still serving in the parliament has "damaged the public service". The PM&C secretary is out of line??? Tony Abbott (@TonyAbbottMHR) December 6, 2017
Dr Parkinson, who led the Rudd government's climate change department and was an advisor to Labor treasurer John Dawkins, said some of the fall out from the high profile sackings had since been ameliorated, "but there's no question that for the service as a whole, I think it came as quite a shock."
He said he retained a professional relationship before leaving Treasury, describing Mr Abbott as consultative, honest and respectful.
More than 15,000 public service jobs have gone nation wide since Mr Abbott's 2013 election win, while doubling its spend on contracts with the big four consultancy firms to nearly $1 billion.