At 0630 GMT, the rand traded at 14.5730 versus the dollar, 0.2pc weaker than its previous close.
Analysts polled by Reuters have predicted a 0.1pc GDP growth in the third quarter in seasonally-adjusted quarter-on-quarter terms, following a 3.1pc expansion in the second quarter.
Statistics South Africa will release the data at 0930 GMT.
Almost two years after taking office, President Cyril Ramaphosa has struggled to get Africa's most industrialised economy firing on all cylinders.
Investment levels and business confidence remain weak.
Government bonds were flat on Tuesday, with the yield on the benchmark 2026, instrument at 8.46pc.