The Federal Capital Advisory Committee was appointed to advise the Government on matters concerning the construction of the Federal Capital. The members of the Committee were Mr (later Sir) John Sulman, Mr E.M. de Burgh, Colonel P.T. Owen, Mr J.T.H. Goodwin (all appointed 26 January 1921) and Mr H.E. Ross (appointed 2 March 1921). 
The functions of the Committee were to inquire into and advise upon the following matters in relation to the construction of the Federal Capital at Canberra:-
(1) The existing data, plans and works.
(2) The works, buildings and city services that can be further
    proceeded with or commenced forthwith.
(3) A general scheme upon which to develop the buildings of the
    Capital city progressively, having regard to both official and
    civil occupation.
(4) Proposals for the design and construction of the necessary 
    works, buildings, and services.
(5) The order in which essential surveys and the construction of
    such works, buildings, and services shall be undertaken.
(6) Such matters as in the opinion of the Committee are expedient, 
    in regard to provision and manufacture of materials necessary for
    the purposes of construction.
 And to inquire into and report upon any special matter in
 relation to the lay-out and construction of the Federal Capital
 city, as and when directed by the Minister for Works and
 Railways.

The Secretary of the Committee was Mr C.S. Daley, of the Public  Works Branch of the Department of Works and Railways. The Committee met 71 times in its four years of active life, mainly in Sydney but also in Canberra and Melbourne.
The Committee was not abolished until 30 June 1925, although it had not had any formal business since 3 December 1924, and the Federal Capital Commission had assumed control of the Federal Capital Territory on 1 January 1925. 

The committee produced three reports, viz:
 Construction of Canberra. First general report, 18 July 1921  (Parliamentary Papers. Session 1920-21. Volume III, Paper
 No. 134, pp. 2027-2069)
 Construction of Canberra. Second general report, 31 July 1922.  (Parliamentary Papers, Session 1922. Volume II, Paper No. 41, 
 pp. 2791-2804)
 Construction of Canberra. Final report, 25 May 1926.
 (Parliamentary Papers. Session 1926-27-28. Volume II,
 Paper No. 56, pp. 1037-1080.

This final report was produced as a review of the Committee's  operations overall, with the intention of explaining its principles to the body taking over its functions, the Federal Capital Commission.

Sources
Executive Council Minute 22 January 1921,
CRS A1573, Works and Railways 1921
Commonwealth of Australia Gazette, No. 11, 3 February 1921
Minutes of first meeting of Federal Capital Advisory
Committee, CRS A411, 27 January 1921
Executive Council Minute 2 March 1921,
CRS A1573, Works & Railways 1921
Commonwealth of Australia Gazette, No. 24, 17 March 1921
Appointment of Col. P.T. Owen - Correspondence
files - CRS A414 item 1 - Appointment of Committee, 1921-1928 Extract from Minutes of seventh meeting of Federal
Capital Advisory Committee - CRS A411
 Appointment of C.S. Daley as Secretary from CRS A414
item 5 'Appointment of Secretary', 1921-1923
Executive Council Minute 20 June 1925,
CRS A1573, Works & Railways 1925
Commonwealth of Australia Gazette, No. 54, 9 July 1925
Minutes of 71st meeting of Federal Capital Advisory
Committee and notes of meeting with Minister for Works
and Railways - CRS A411
Extract from Minutes of 11th Meeting of Federal Capital
Advisory Committee - CRS A411
Extract from Minutes of 16th meeting of Federal Capital
Advisory Committee - CRS A411
Extract from Minutes of 47th meeting of Federal Capital
Advisory Committee - CRS A411
Letter from Sir John Sulman to Mr J.H. Butters (chairman
of Federal Capital Commission) and letter from C.S. Daley
to Sulman - CRS A414 item 92 'Final Report of Fed eral
Advisory Committee', 1924-1926
Federal Guide, 1921, p.55 and 1924, p.46-7
Seat of Government (Administration) Act 1924
 

Historical agency address
Customs House, Sydney. (Meetings were sometimes held in Canberra and Melbourne)
Legislation administered
Creation : Executive Council Minute No 6 of 22 January 1921 Supplemented by Minute No 15 of 2 March 1921
Abolition: Executive Council Minute No 32 of 20 June 1925