Quoting from Brian Bunting’s The Rise of the South African Reich, pages 43–5, one of the Union of South Africa’s most formidable and influential organizations…

was the Afrikaner Broederbond (Association of Brothers), a secret society which has gradually come to assume a dominant position in the affairs of the volk. The Broederbond was formed in 1918 and maintained an open existence until 1924, when it went underground and its affairs became largely a matter for conjecture. An elite organization, its membership was stated in 1944 to be 2,672, of whom 8.6 per cent were public servants and 33.3 per cent teachers. In 1952 the Rev. V. de Vos, who had broken away from the Nederduitse Gereformeerde Kerk in 1944 and formed a Reconstituted Dutch Reformed Church because the N. G. Kerk, he alleged, was dominated by members of the Broederbond, gave the following breakdown of Broederbond membership: 357 clergymen, 2,039 teachers, 905 farmers, 159 lawyers, and 60 M.P.s. [In the 1960s] the membership of the Broederbond [was] estimated to be in the region of 7,000. Its general mode of operation has been to coordinate activities among Afrikaners and to ensure that Broeders are placed in key positions which can then be utilized for the advancement of the volk.

[…]

In an article in the Sunday Times on 8 March 1964 Mrs Janie Malherbe, wife of South Africa’s war‐time Director of Military Intelligence and herself a Captain in Military Intelligence during the war, described the forces which had been at work in the Broederbond during the thirties:

This terrifying, octopus‐like grip on the South African way of life was made possible by reorganising the Broederbond on the pattern of Hitler’s highly successful [Fascist] state, complete with fuehrer, gauleiters, group and cell leaders, spread in a sinister network over the whole of South Africa. This was initially planned by a high‐ranking Nationalist and two Stellenbosch students who were sent to Germany, at Nazi expense, to study the Nazi cell system.
The man who planned this in consultation with the then Nationalist leader Dr Malan was Graf von Durckheim Montmartin.

[Berlin] had sent Montmartin to South Africa in 1934, ostensibly to attend an educational conference, but in reality, as was subsequently discovered from captured German documents, to consult secretly with Broederbond leaders, in order to foment a plan which would ensure that South Africa would side with Germany in the world war which [the Fascist bourgeoisie] was then already engineering.
Mrs Malherbe writes:

The immediate result of his visit was the reorganisation of the Nationalist Broederbond on the Nazi system, the main difference being that where Hitler re‐invoked the rites of the German pagan Gods to promote his ideologies, the Nationalists’ Broederbond declared that their plan of complete domination of white South Africa, and absolute subjugation of the non‐whites, was an implementation of South Africa’s ‘God‐given destiny’. This was a clever ruse, for by its means the powerful Dutch Reformed Churches could be roped in.

(Emphasis added.)