MacArthur began organising large scale intelligence services shortly after his arrival in Australia. On 15 April 1942, the joint Australian-US Central Bureau signals intelligence organisation was established at Melbourne. Central Bureau's headquarters moved to Brisbane in July 1942, and Manila in May 1945. Australians made up half the strength of Central Bureau, which was expanded to over 4,000 personnel by 1945. The Australian Army and RAAF also provided most of the Allied radio interception capability in the SWPA, and the number of Australian radio interception units was greatly expanded between 1942 and 1945. Central Bureau broke a number of Japanese codes and the intelligence gained from these decryptions and radio direction finding greatly assisted Allied forces in the SWPA.