South Africa's Purchasing Managers' Index (PMI) fell for the fourth straight month to a seasonally adjusted 44.2 in July from 53.9 in June, sponsor Kagiso Securities said on Monday.
PMI dropped 9.7 points to a two-year low in July, falling into contraction territory for the first time since October.
"The Kagiso PMI has been losing ground for the fourth consecutive month and declined to a level significantly below the latest readings on the global PMI," said Abdul Davids, head of research at Kagiso Asset Management.
Factory activity in South Africa's major trading partners China and Europe also slowed as manufacturing globally lost momentum.
Kagiso said strike activity during July impacted the business activity sub-index, which dropped nearly 20 points, and led to some of the drastic decline in the PMI.
South Africa's annual strike season is in full swing and sees gold, coal and platinum workers meeting with employers to try and end a strike that analysts see weighing on GDP growth in the second quarter.
All but three of the sub-indice went into contraction in July and new sales orders, which is the largest weighted sub-category, lost nearly 10 points.