By Alex Mitchell in Canberra

HOME Affairs secretary Mike Pezzullo will stand down while the public service commissioner investigates leaked text messages he sent to a Liberal Party powerbroker.

A plethora of encrypted texts revealed by Nine Newspapers on Sunday night show Mr Pezzullo using a political back channel to two former Liberal prime ministers.

The texts indicate he used Liberal powerbroker Scott Briggs to wield influence, including suggesting ministerial sackings and which MP should become minister of his department.

Prime Minister Anthony Albanese confirmed on Monday morning Mr Pezzullo had agreed to stand aside while the investigation occurs.

Home Affairs Minister Clare O’Neil, who initially referred the matter to the public service’s oversight body, had asked him to stand down.

“He has agreed to stand aside, that action is appropriate,” the PM told reporters.

“We’ll await the findings of the investigation which we will expedite, we have a cabinet meeting (on Monday) where no doubt I’ll be able to get further reports about that.”

But Opposition Leader Peter Dutton – who was home affairs minister when Mr Pezzullo was secretary – defended him and suggested the leaking of text messages should be referred to federal police.

The texts showed Mr Pezzullo suggested Mr Dutton should become the new home affairs minister the night before Scott Morrison ousted Malcolm Turnbull from the prime ministership in 2018.

“(Mr Pezzullo) was able to, in all of his interactions, put the country first… he had a passion for home affairs because he believes very strongly in national security and border protection,” Mr Dutton said.

Earlier, a Greens senator and a refugee advocacy body called for Mr Pezzullo to quit.

Greens Senator Nick McKim said it was “an abject failure to understand … the difference between being a public servant and a politician”.

“These messages along with years and years of arrogance, of failure to accept responsibility, of failure to understand the principle of accountability … a litany of scandals and failures he has overseen in the Home Affairs department …(show) his position is untenable,” he told ABC Radio.

“If he’s not working on his resignation letter to (Prime Minister Anthony) Albanese, he certainly should be.”

Texts showed Mr Pezzullo suggested now Opposition Leader Peter Dutton should become the new Home Affairs Minister the night before Scott Morrison took the PM role from Malcolm Turnbull in 2018.

According to the messages, he suggested the Liberals sack former defence minister Christopher Pyne, labelled former defence minister Marise Payne “completely ineffectual” and “a problem”, and said he “almost had a heart attack” when Julie Bishop was linked with a tilt at the prime ministership in 2018.

Others show Mr Briggs directly asking if Mr Pezzullo had any messages he wanted him to convey before a dinner with Mr Morrison and Mr Turnbull.

It is not suggested the messages show corrupt or illegal conduct but arguably that Mr Pezzullo overstepped the required impartial nature of heading a government department.

Mr Pezzullo was the first person appointed to head the Home Affairs Department when it was created in 2017.

Refugee Action Coalition’s Ian Rintoul said the government should sack him, but added he was a “symptom of the sick system Labor has kept in place”.

“It is not just Pezzullo that needs to go,” he said in a statement.

“Pezzullo epitomises the punitive mentality that characterises the Home Affairs department, and is bolstered by Labor’s on-going support of Operation Sovereign Borders.”