Old soldiers never die. They just move into the most senior posts in Australia's national security community.

A quiet parade of decorated current and former Army officers have been making their way into the most powerful positions within intelligence agencies, big-spending defence procurement posts and even vice-regal offices.

Ex-military appointments to civilian posts are nothing new, but what's raising eyebrows among some in the defence community is the remarkable trend running in favour of Army officers over their service cousins in the Navy and Air Force.

Members of the khaki cavalcade include Commander-in-Chief Peter Cosgrove (and the next Governor-General David Hurley), key appointments to Government ministries, and even the directors of the country's intelligence agencies.

When Scott Morrison announces his new frontbench it's expected to include former Army Reserve brigadier Linda Reynolds as Defence Minister, and two other former Army officers, Stuart Robert and David Fawcett, are in the running for other Defence portfolios.

Perhaps the most high profile Army officer to enter federal politics in recent years is former SAS Captain Andrew Hastie, who now chairs Parliament's Joint Committee on Intelligence and Security.

Former SAS Captain Andrew Hastie is now the MP for Canning, Western Australia. ( ABC News: Jed Cooper )

In Australia's secretive intelligence community, Army is also making its mark in a world that is typically dominated by career diplomats and bureaucrats.

Mike Pezzullo, the former defence bureaucrat who heads the recently expanded and all-powerful Home Affairs Department, was once also an Army Reserve officer.

It's expected that Linda Reynolds will be announced as Defence Minister by Mr Morrison. ( AAP: Lukas Coch )

The Director-General of Australia's domestic spy agency ASIO is former Army Major General Duncan Lewis, a decorated SAS soldier who went on to an impressive civilian career in diplomacy and at the top levels of the public service.

ASIO director-general Duncan Lewis. ( ABC News: Marco Catalano )

Similarly Paul Symon, the head of Australia's overseas spy agency ASIS, is also a former Major General and Deputy Army Chief.

At the Australian Signals Directorate a possible future Army Chief, John Frewen, has become Deputy Director General with the "3 star" rank of Lieutenant General.

At the very top of the ADF, Army is currently in a commanding position — "4 star" General Angus Campbell is Chief, but directly below him are two Army "3 star" officers; the soon-to-be Commander of Joint Operations Greg Bilton, and Army Chief Lieutenant General Rick Burr.

The Defence Department is led by Secretary Greg Moriarty who as an Army Reserve Officer was posted to the Headquarters of US Central Command during the first Gulf War.

Below him another former Army Officer, Tony Fraser, serves as Deputy Secretary heading up Defence's Capability and Sustainment Group.

Lieutenant General Angus Campbell spearheaded the coalition government's efforts to "stop the boats". ( AAP: Andrew Taylor )

At the Department of Veterans' Affairs another former Major General, Liz Cosson, has become Secretary after a trailblazing career in the Army.

Army insiders say the prevalence of their people currently serving in top national security posts is not surprising given the high tempo of operations the service had in recent decades.

And in a gesture of goodwill to their Navy and Air Force colleagues they point out that all things in Defence are cyclical — meaning that despite its size, Army won't always dominate the ADF's leadership positions.

The khaki cavalcade:

Governor-General: Peter Cosgrove, then David Hurley

Minister for Defence: Linda Reynolds

Defence Industry Minister: potentially Stuart Robert or David Fawcett

Chair of the Joint Intel Committee: Andrew Hastie

CDF: Angus Campbell

Chief of Army: Rick Burr

CJOPS: Greg Bilton (taking command in June)

Home Affairs Secretary: Mike Pezzullo

Veterans' Affairs Secretary: Liz Cosson

Defence Secretary: Greg Moriarty

Deputy Secretary: CASG Tony Fraser

Director General ASIO: Duncan Lewis

Director General ASIS: Paul Symon

Deputy Director General ASD: John Frewen

Defence Intelligence Organisation: Matthew Hall