 Though not explicitly provided for by the South Africa Act, the office of Prime Minister of South Africa was quickly established as the head of government and, like other government ministers, the Prime Minister was required to be a Member of either House of Parliament.As in other British Dominions, the Governor-General appointed the leader of the largest political party in the lower house of Parliament as Prime Minister.Prime Ministers were also sworn in as Executive Councilors if they were not already members of the Executive Council.