The yield on the 2015 bond fell three basis points to 5.58 percent, while that for 14-year paper was unchanged at 7.6 percent.

The rand was at 8.4292 to the dollar at 0710 GMT, largely unchanged from Monday's close in New York of 8.4375.

It hit a low of 8.4500 on Monday, levels last seen at the end of July, as trading volumes declined due to a public holiday in the UK.

Labour unrest at Lonmin's Marikana mine, where 44 people were killed earlier this month following a violent confrontation between rival unions, has also put pressure on the rand.

"It's hanging on to its weaker undertone, which tells me that the market is still nervous," said Nilan Morar, head of trading at Global Trader. "It also doesn't help much that this is aggressively being broadcast pretty much across the world."

Morar said the GDP data, expected at 0930 GMT, could influence the direction of the rand. Economists expect growth to have accelerated to 3.3 percent, from 2.7 percent previously.

"I think we could see the rand strengthen a bit," he said. "To a large degree, they're anticipating a stronger number anyway. If there's any disappointment in that we could hang on to these weaker levels."