South Africa's rand edged up on Wednesday but most traders were hesitant to make any significant moves before Finance Minister Pravin Gordhan spells out how government plans to boost economic growth to avert a sovereign ratings downgrade.

Traders said most trading in the session would likely come after the budget as the country and certainly foreign investors eagerly await Gordhan’s proposals on how he is going to try and fix the fiscal situation in the country.

But it was clear that the rand is struggling to make meaningful gains given the risk-on global market environment has run out of steam, traders added.

"Gordhan will attempt to walk tightrope of reigning in fiscal budget while not sabotaging what little economic growth momentum South Africa has left," said NKC African Economics analysts in a note.

"Should he succeed, we should see the rand break through technical barriers around psychological 15.0000 level against the dollar."

Stocks were set to open lower at 0700 GMT, with the JSE securities exchange's Top-40 futures index down 1.14 percent.

Shares in Aspen Pharmacare rose 9.4 percent to 289 rand on Tuesday after the drugmaker said it expected its interim earnings to be as much as 23 percent higher.

Bonds were mostly weaker, adding 0.5 basis points to 9.165 percent.