Nick Warner retires as Office of National Intelligence chief

Mr Warner has led the Office of National Intelligence since it was formed following a major overhaul of Australia's national security apparatus in 2018.

He also led the agency's forerunner, the Office of National Assessments, from 2017 and before that was head of the Australian Secret Intelligence Service starting in 2009.

Prime Minister Scott Morrison on Friday afternoon announced Mr Warner would retire from the ONI when his term ended in December and thanked him for his service.

"Nick has an extremely long and distinguished career serving Australia's interests and defending and protecting Australia's interests," Mr Morrison said.

"He's a great Australian, who has done an outstanding job, spanning some four decades in areas of national security, foreign policy and so many other areas."

The Office of National Intelligence was established following a major review of Australian intelligence agencies, and provides the government assessments of international developments using information collected by other intelligence and government agencies.

Mr Warner is a former Department of Defence secretary and was a senior international adviser to prime minister John Howard. He held several senior roles within the Department of Foreign Affairs and Trade and was high commissioner in Port Moresby between 1999 and 2003 and ambassador in Tehran from 1994 to 1997.

Mr Morrison flagged Mr Warner could still assist the federal government on national security matters on a less formal basis.