Australia's government on Monday fired a powerful civil servant known as a hardliner on immigration following an investigation into WhatsApp messages he reportedly sent to sway senior politicians.

Michael Pezzullo was sacked as head of the Department of Home Affairs after a two-month independent probe found he had breached the public service's code of conduct at least 14 times. 

Allegations against Pezzullo included failing to act apolitically, using his power to benefit himself, and engaging in "gossip and disrespectful critique" of ministers and colleagues, the Public Service Commission said.

Prime Minister Anthony Albanese confirmed Pezzullo's appointment had been "terminated" following the inquiry, launched in September after media reports exposed his alleged communications.

Pezzullo came unstuck in September when The Age and 60 Minutes published hundreds of encrypted WhatsApp messages he had allegedly sent to influence previous conservative governments.

In one of the WhatsApp messages to a Liberal Party power broker, he reportedly called for a "right winger" to be installed as his minister responsible for immigration, adding: "People smugglers will be watching."

"There will be no tears for Michael Pezzullo," said Ian Rintoul, spokesperson for Australia's Refugee Action Coalition.

Pezzullo had been kept in place by successive Australian governments as a "departmental attack dog" for their harsh immigration policies, Rintoul said in a written statement sent to AFP.

Rintoul said he doubted the civil servant's removal would end the center-left Labor government's strict anti-immigration stance, which has included sending asylum seekers to the Pacific island of Nauru.

The government rushed through a law this month empowering it to impose home curfews and ankle bracelets on scores of migrants with criminal convictions after a High Court ruling forced their release from detention.