456 Mr John Curtin, Prime Minister, to Dr H. V. Evatt, Minister for External Affairs (in Washington)
Cablegram PM21 CANBERRA, 4 April 1942
MOST IMMEDIATE MOST SECRET
Reference your PMS.23.  The following appreciation has been
furnished by the Australian Chiefs of Staff with General Brett 
co-opted as the representative of General MacArthur :-
The Japanese, having completed their conquest of the Netherlands
East Indies, and possessing decisive air superiority and effective
control of the seas in the areas in which they are operating, are
in a position to launch further attacks in the South West Pacific.
Attacks in force against Australia and Australian lines of
communication are likely at an early date.
2. The area in Australia vital to the continuance of the war
effort lies on the east and south east coast, generally between
Brisbane and Melbourne. Port Moresby is the key to this area. An
attack in force on Port Moresby could develop at any time. There
is an accumulation of evidence of the movement of enemy forces in
the direction of Rabaul where there is already a formidable
concentration. This threat is most serious, not only because the
indications are that an attack is impending, but also because any
success would imperil both the lines of communication between
Australia and the United States of America, and the security of
the vital area of Australia. Were it not for successful attacks on
the Japanese in this area, an attack on Port Moresby would have
been made before now.
3. Early attacks are also likely on both the following areas:-
4. If Darwin were properly defended and bomber aircraft and Naval
forces based there, attacks could be launched against the enemy in
the Netherlands East Indies which might contain the enemy in that
area and prevent reinforcement elsewhere, and which would prepare
the way for an eventual offensive.
5. Fremantle is also open to attack and the risk of sporadic raids
by carrier-borne aircraft is very real.
6. In all the foregoing front line areas there are not sufficient
forces available to secure their defence, much less to take the
offensive which is all important. The requirement of greatest
urgency is for increased Naval and Air forces to protect these
7. The minimum Naval forces required for operations to the north
east of Australia is the Anzac squadron reinforced by two task
forces which should include two or three aircraft carriers, and
should be based in the area. A squadron of submarines is also
8. The first priority requirement of aircraft is for aircraft to
equip with modern planes the existing operationally trained
R.A.A.F. and United States air corps units. Taking into account
the aircraft already here and known to be en route, the aircraft
necessary for this purpose are as follows:-
These figures provide for 25% wastage.
9. Of these aircraft the most urgently needed are heavy bombers
and the importance of the immediate supply of these cannot be
10. With the foregoing forces, it should be possible to undertake
initial offensive operations against enemy bases, particularly
11. The foregoing relates merely to immediate requirements but it
is necessary to keep constantly in mind the need for combined
offensive operations on such a scale as will draw off the Japanese
forces that are now available for further attacks.
12. In this connection it is desirable to stress the need for
combining initial offensive operations with the building up of the
forces that are required to undertake a major offensive, and in
particular to emphasise the importance of keeping in the forefront
of our policy the need for building up an Allied Naval force of
sufficient strength to challenge the Japanese fleet at any moment.
Such a project should be constantly in our minds, whilst the
tactical groups of which this force will be composed should be
continually employed in offensive operations until such time as
the moment for concentration arrives. Ends.
2. I have discussed it with General MacArthur who is repeating it
directly to General Marshall.  He is in entire agreement with
the appreciation and urges that the provision of Naval forces as
proposed and the aircraft indicated are the minimum essential for
the purposes indicated. You are requested to seek the acceptance
of these views and the early provision of the forces and equipment
3. This cablegram is being repeated to Bruce in London, so that he
can also support it there. 
[AA:A981, WAR 33, ATTACHMENT C]