Adcorp estimates that in the last decade the economy has lost R55.2-billion cumulative terms due to sickness.
Adcorp's latest employment index raises concerns about the increasing number of sick days being taken by staff and how it is impacting the economy.
The index shows that since 2000, the number of sick days has increased 466% from 0.7-million to 3.96-million in 2013, despite employment itself remaining relatively flat over the decade.
Loane Sharp, labour economist at Adcorp Holdings, said sick leave can have a disruptive effect on supply chains and may have contributed to the "growing phenomenon of temporary or contingency workers".
Between 2009 and 2011, a quarter of all workers claimed the maximum statutory allowance for sick leave – 36 days in a three-year cycle. This has had an impact on productivity and output.
Adcorp said in a statement: "The average output per worker in 2012 was R145 233 per year – or R586.19 per working day – in 2011, this loss of output due to sickness totalled R4.29-billion.
"It is alarming that sick leave in South Africa has been rising continuously over the past decade, and at present shows no signs of reversing," said Sharp.
The index also showed that the economy shed 34 654 jobs in August. The bulk of jobs lost were permanent jobs in the mining, construction, transport and financial services sectors. Last month, 26 820 permanent jobs and 12 845 temporary jobs were lost.