The mandarin in charge of the Attorney-General's Department, Roger Wilkins, will step down from his $700,000 a year position when his term ends at the end of this month to continue a massive shake-up of the federal public service's power structure.
Six department heads have now either been sacked or have resigned since the Tony Abbott came to power almost a year ago.
A statement from the Prime Minister's office said Mr Wilkins had a distinguished public service career, having led the department since September 2008.
Mr Wilkins, a man known for his love of bow ties, had been director-general of the Cabinet Office in New South Wales from 1992 to 2006 and was the director-general of the NSW Arts Ministry from 2001-2006.
''I thank him for his contribution to public life in Australia and wish him well for the future,'' a statement from Prime Minister Tony Abbott said.
''I will announce arrangements for the position of the Secretary of the Attorney-General's Department in the near future."
High-ranking secretaries in the federal bureaucracy who served in the Labor era are slowly leaving the public service.
Treasury secretary Martin Parkinson will leave this year.
Finance Department secretary David Tune lodged his resignation in May.
Just after Mr Abbott won office, he sacked Industry Department head Don Russell, Energy boss Blair Comley and Agriculture secretary Andrew Metcalfe.
In an interview with News Limited just before he took up the job at the department in 2008 in which he was described as a safe pair of hands, Mr Wilkins, who could read Kant in the original German, said his goal was to give up smoking.
It was not known whether the elite public servant, now aged in his 60s, was successful in this.
Mr Wilkins' website biography said he also served as Citi's head of government and public sector group Australia and New Zealand and was Citi's global public sector leader on climate change from 2006-2008.
Mr Wilkins has chaired several national taskforces and committees dealing with public sector reform, including the Council of Australian Government committee on regulatory reform, the national health taskforce on mental health and the national emissions trading taskforce.
Mr Wilkins was the vice-president of the financial action taskforce for 2013-14 and is president for 2014-15.