Why did the South African government suspend influx control during World War II?

During World War II, the South African government under Prime Minister Jan Smuts suspended the operation of influx control on the Witwatersrand primarily due to labor shortages.1

As many white workers left to serve in the military, the country's manufacturing sector experienced a significant boom and faced an urgent need for labor. By relaxing these restrictions, the government allowed for a massive influx of Black workers into urban areas to sustain industrial production. This policy shift resulted in the Black population of Johannesburg nearly doubling to over 400,000, leading to rapid urbanization and the emergence of informal squatter camps, as housing construction had largely stalled during the war.1