The rand was slightly firmer but has been trapped in ranges, lacking momentum to move outside familiar levels.

The National Treasury on Wednesday tabled a narrower than expected budget deficit of 4.6 percent of gross domestic product in the financial year ending March 2013 from a 4.8 percent shortfall in 2011/12.

Bonds initially gained after that announcement but later reversed those gains on closer analysis of the numbers.

"There is a bit of scepticism about the revenue on the budget, some quarters of the market are saying maybe the reductions in the budget may be too quick and probably too large as well," said a bond dealer in Johannesburg.

The yield on the 2015 bond was up three basis points to 6.645 percent and that on the 2026 issue went up 3.5 basis points to 8.29 percent.

The rand was trading at 7.71 against the dollar at 0640 GMT, a tad firmer than Wednesday's New York close of 7.7350. But dealers don't expected significant gains in the session on the back of lower global market and softer commodities.

"The rand is unlikely to prosper against such a backdrop. Also, given recent history, the rand is unlikely to have much of a reaction to PPI data," said Standard Bank in a note.

PPI data will be released at 0930 GMT, with the market expecting it to slow at 9.5 percent year-on-year from 9.8 percent in December.

On the bourse, stocks futures pointed to a flat start on the at 0700 GMT, with the JSE's blue-chip Top-40 March futures contract inching up 0.07 percent before the start of trade.