The Australian Border Force Commissioner Roman Quaedvlieg has been sacked after a review found that his conduct with a younger female staffer was inappropriate.
The decision comes following reports Governor-General Peter Cosgrove was preparing to sack Mr Quaedvlieg on advice from the government over allegations he abused his power by helping his partner get work at Sydney Airport.
Mr Quaedvlieg refused to resign from the role.
"I had been given a short opportunity to resign prior to termination, however, I chose not to do that as it is tantamount to a concession of culpability, which I strenuously deny," Mr Quaedvlieg said in a statement to media outlets.
A statement outlining the grounds of termination reads that the governor-general, acting on the recommendation of the government, had terminated Mr Quaedvlieg under section 21 of the Australian Border Force Act 2015.
Mr Quaedvlieg's appointment was terminated on grounds of misbehaviour and inconsistent conduct in accordance with the ABF Act.
Australian Governor-General Sir Peter Cosgrove Source: AAP
"Mr Quaedvlieg acted at particular times to modify policies relevant to recruitment processes so as to advantage... a particular candidate for ABF employment," the statement read.
"Additionally, he engaged in acts, and made omissions, which materially advantaged that candidate over other comparable candidates for ABF employment, and on that basis, his conduct amounted for misbehaviour and was inconsistent with his affirmation."
"It's at a sensitive time so I just don't have any public comment to make," Peter Dutton told 2GB radio on Thursday.
"I feel for him and his girlfriend, for his ex-wife and children, it's not an easy situation."
The federal executive council, which includes the governor-general and the prime minister, met in Canberra on Thursday to determine Mr Quaedvlieg's fate.
The statement on the grounds of termination was later published online.
Mr Quaedvlieg conduct has been the subject of two confidential reports, one from the corruption watchdog and one from the head of the prime minister's department.
Attorney-General Christian Porter had been mulling over the reports in recent weeks before the decision was made.
"Needless to say it is extremely unfortunate that it was necessary to terminate Mr Quaedvlieg's appointment," Mr Dutton said in a statement after the sacking was announced.
"He has provided long and conspicuous public service in the critically important areas of law enforcement and national security."
Mr Quaedvlieg has been on paid leave since May last year, earning more than $500,000 while off work.
