Chief of Navy's Personal Distinguishing Flag

The Chief of Navy’s Personal Flag was originally that of the Australian Naval Board. The flag was a derivative of the flag of the British Admiralty and its origin can be traced with certainty to 1633, although it is believed to have been in existence, if not in approved form, before that.
The inaugural First Naval Member of the Australian Naval Board, Rear Admiral WR Creswell, RAN, proposed an Australian version of the flag in 1912 advising the then Minister for Defence:

It is desirable that a flag of the Naval Board be adopted and the proper salute accorded it.

A design, comprising a horizontal gold Admiralty pattern anchor on a horizontally bisected field, the upper half maroon and the lower half royal blue, was subsequently approved by King George V and from 20 May 1920 it was flown outside the premises occupied by the Naval Board until 9 February 1976 at which time it was hauled down following a reorganisation of the Department of Defence that saw the abolition of the Naval Board. Please see Navy News article:

The Naval Board Flag is lowered for the last time adjacent to what is now building R8 at Russell Offices on 9 February 1976.

The flag was later reintroduced as the Chief of Navy’s (CN) personal flag and was first hoisted on 1 January 1981. It is presently flown continuously outside building R1 at Defence Headquarters, Russell Offices, Canberra and struck or shifted only by order of CN.

The Chief of Navy's flag is flown continuously outside Defence Headquarters in Canberra alongside those of the Chief of Defence Force, Vice Chief of the Defence Force and the other Service Chiefs.

Occasions on which CN's flag is shifted include official visits to warships and commissioned establishments. Smaller versions of CN's flag are also used to denote his presence in Service boats, Service aircraft and on cars during official calls and visits.

The Chief of Navy's Personal Flag denoting his official presence during a visit to an RAN fleet unit.
Chief of Navy's staff car displaying his personal flag, star plate and unique license plate.