It was established after South Africa became a republic and withdrew from the Commonwealth of Nations, cutting ties with British intelligence which had become weaker due to the system of Apartheid.
[1]: Chp2 The British authorities squashed any chance of an early national intelligence service, based on MI5, being created in 1938 as they feared that it would be infiltrated by nationalist Afrikaners, the Ossewabrandwag and Nazi sympathisers.
[1]: Chp2 Colonel Pierre de Villiers, Chief of South African Police and the countries liaison with MI5, approached MI5 in 1938 in an attempt to set up a security organisation based on the latter.
[1]: Chp2 In September 1940, the Defence Advisory Committee, under the chairmanship of Denys Reitz, reported their concerns about the confusion, overlapping of information and delays when it came to the collection and distribution of intelligence.
[2]: 215 Headed by Colonel Lenton weekly meeting were held and attended by representatives for censorship, intelligence, SAP, railway police, treasury, immigration and customs.
[4]: 436 Attached to the Prime Minister's office, he would be in command all security and intelligence chiefs in the country including the military, and reported only to Vorster.