CANBERRA, Australia (AP) — A senior Australian public servant has stepped aside, authorities said Monday, while an investigation is underway into allegations that he sent encrypted messages in order to undermine some ministers and promote others to further his own career.

Michael Pezzullo has been secretary of the Department of Home Affairs since it was created in 2017, bringing together the Australian Security Intelligence Organization, Australian Federal Police and Immigration and Border Protection.

On Sunday and Monday, a television network and newspapers owned by Nine Entertainment published messages that he had allegedly exchanged over a period of five years, starting from 2017, with businessman Scott Briggs, who was close to former conservative Prime Minister Scott Morrison and his predecessor, Malcolm Turnbull.

Home Affairs Minister Clare O’Neil said she had referred the allegations to the Australian Public Service Commission which will investigate the matter. Pezzullo’s job required him to remain apolitical and independent of politics.

The messages on encrypted apps WhatsApp and Signal, suggested a preference for right-wing faction of the conservative Liberal Party over so-called moderates. They also included criticism of former Attorney-General George Brandis.

When Peter Dutton quit as home affairs minister in 2018 to challenge Prime Minister Turnbull for the top job in a ballot of government lawmakers in 2018, a message attributed to Pezzullo suggested right-wing ministers Angus Taylor or Alan Tudge should replace him.

“Any suggestion of a moderate going in would be potentially lethal viz OSB,” the message said, referring to the contentious Operation Sovereign Borders under which asylum seekers’ boats were turned back at sea.

The leadership contest ended with Scott Morrison as prime minister and Dutton returned to his home affairs portfolio.

Prime Minister Anthony Albanese said O’Neil, the home affairs minister, had directed Pezzullo to stand aside and he had agreed pending the investigation result.

The allegations would be investigated by former Australian Public Service Commissioner Lynelle Briggs.

Pezzullo did not reply to requests for comment. O’Neil’s office did not respond when asked whether Pezzullo would continue receiving his pay during the probe.

“We’ll await the findings of the investigation, which we will expedite,” Albanese told reporters. “We’ll make no further comment on the specifics for obvious reasons.”

The allegations pre-date Albanese’s center-left Labor Party coming to power in elections last year.

Dutton, who is now opposition leader, said Pezzullo had always “conducted himself in a thoroughly professional way in my dealings with him.”

Griffith University governance and public integrity expert A.J. Brown said Pezzullo appeared to breach core principles of accountability and good conduct that department heads are bound by.

“Our whole system of government relies on trust. It relies on the public being able to trust that senior public servants are not entering into political games and political manipulation,” Brown told Nine.

Scott Briggs, the businessman, confirmed the authenticity of the exchanges with Pezzullo which he described as “private matters.”

The minor Greens party called on the government to fire Pezzullo if he did not resign.

“His failure to respect the boundaries between politics and the public service mean that his position is untenable,” said Greens immigration and citizenship spokesperson Sen. Nick McKim.