The rand was trading at 7.6183 to the dollar at 0634 GMT, over half a percent firmer than Tuesday's New York close of 7.662.

The central bank said net gold and foreign exchange reserves increased to $49.639 billion at the end of February from $49.072 billion in January while gross reserves were up to $51.889 billion from $51.451 billion in the January.

The Chamber of Commerce and Industry is due to release its February Business Confidence Index at 0930 GMT.

"We have really struggled to ratchet higher. I think we're going to look at something like 6.57-6.67 as a range to begin with, and then continue to follow the euro intra-day," said Jim Bryson, a trader at Rand Merchant Bank.

Trade union group COSATU is planning a mass protest on Wednesday against short-term labour agencies and road tolls being introduced around Johannesburg, although analysts said there would be no impact on currency or bond markets.

Yields on both the two main benchmark government bonds were up one basis point, with the 2015 yield at 6.73 percent and that on the 2026 note at 8.34 percent.

Stocks opened higher, with the JSE's blue-chip Top-40 up 0.26 percent shortly after the 0700 GMT start of trade.