The Department of the Cabinet Office was created on 11 March 1968 (Commonwealth of Australia Gazette, No 22A, 12 March 1968), replacing Secretary to Cabinet/Cabinet Secretariat [I] within Prime Minister's Department.
 
The functions of the new Department were to service the Cabinet and Cabinet Committee, thus assisting the Prime Minister in the
expeditious ordering of Cabinet business and proceedings and ensuring that Cabinet decisions were implemented promptly and efficiently.  
The then Prime Minister, Mr Gorton, was responsible for the Department of the Cabinet Office during the life of the Department and Sir John Bunting was Secretary for the entire period.
 
On 12 March 1971 the Department of the Cabinet Office and the Prime Minister's Department (CA 12) were abolished and two new Departments, the Department of the Prime Minister and Cabinet (CA 1401) and the Department of the Vice-President of the Executive Council (CA 1402), were created. The functions of the Department of the Cabinet Office were transferred to the Department of the Prime Minister and Cabinet where they were carried out by Cabinet Secretariat [II] (Cabinet Office) (CA 1472).

Minister of the Department of the Cabinet Office was:
 
11 Mar 1968 - 12 Mar 1971   : Sir John Gorton
 
Secretary to the Department was:
 
11 Mar 1968 - 12 Mar 1971   : Sir John Bunting (CP 91)
 

Historical agency address
West Block, Canberra ACT
Legislation administered
Creation:Executive Council Meeting No. 12 (Prime Minister's Minute No. 8) of 11 March 1968
Abolition: Executive Council Minute No. 14 of 12 March 1971