For years, South Africa's clothing and textile industry has operated largely out of the national spotlight. Yet recent disruptions in manufacturing hubs such as Newcastle in KwaZulu-Natal have revealed how dependent parts of the sector have become on migrant labour. Following anti-migrant protests and the departure of thousands of foreign workers, many factories are now struggling to maintain production, exposing deeper questions about labour markets, wages and the future of South African manufacturing.

Employers say many of the departing workers had valuable sewing skills that are hard to replace quickly, while locals are often unwilling to take the low-paying jobs.

Weeks after xenophobic protests drove thousands of migrant workers from South Africa, rows of sewing machines stood idle at a clothing factory in Newcastle, a manufacturing hub in…