The benchmark Top-40 share index fell 0.47 percent to 47,822 points while the All-Share index dropped 0.44 percent to 54,309 points, with Mediclinic leading the falls after reporting lower annual earnings.

At 1500 GMT, the rand traded at 12.9475 per dollar, 1.13 percent firmer than its overnight close. The currency is trading at its firmest levels since April 24, according to Thomson Reuters data.

In fixed income, the yield on the benchmark government bond due in 2026 dipped 6 basis points to 8.5 percent.

The yield had fallen by as much as 10.5 basis points earlier in the session, reacting to data that showed CPI slowed to 5.3 percent in April from 6.1 percent in March, below market expectations of a 5.55 percent year-on-year rise.

Markets are focused on the South African Reserve Bank's (SARB) interest rate decision on Thursday, with economists polled by Reuters expecting it to keep the repo rate unchanged at 7 percent, although the lower inflation boosted hopes for a rate cut later this year.

"Speculation is likely to remain high on the potential for monetary policy easing later in the year," Elize Kruger, a senior economists at NKC African Economics wrote in a note.

Shares in Mediclinic fell 7.28 percent to 137.00 rand in Johannesburg after London-listed Mediclinic International posted a 19 percent drop in underlying annual earnings that were impacted by regulations in the Middle East that have now been changed.

"Expectations were a whole heap better than what we saw today and the market is reacting," Independent Securities trader Ryan Woods said.

Other losers were among rand-hedged stocks, which make the bulk of their revenue outside South Africa and tend to weaken as the local currency strengthens.

Naspers dropped 0.94 percent to 2778.00 rand, while Richemont fell 1.17 percent to 107.69 rand.