At 1500 GMT the rand was 1.46 percent weaker at 14.4400 per dollar, slightly firmer than the session-low of 14.4975.
The rand briefly traded below the 14.00 mark on Tuesday before giving back those gains, and has since tumbled alongside other emerging markets as investor optimism over the US-Mexico trade deal faded.
Traders said month-end rebalancing by of portfolios, which often sees fund managers and traders buying dollars to match losses by the local currency, had added to selling pressure.
Washington and Mexico agreed on Monday to overhaul the NAFTA trade deal. But the fact that US President Donald Trump's planned tariffs of another $200 billion on Chinese goods could take effect in late September dashed market optimism.
Local jitters over the government's land reform policy have also weighed on sentiment toward the rand.
The rand rallied briefly to 13.9525 earlier after parliament withdrew an expropriation bill passed in 2016 that allowed the state to make compulsory purchases of land.
The thrust of the bill, which sought to make compulsory purchases of land to redress racial disparities in ownership, has been overtaken by a proposal by the ruling African National Congress to change the constitution to allow the expropriation of land without compensation.
"In view of next year's elections this contentious topic is not going to have caused volatility in the rand for the last time," said emerging analyst at Germany-based Commerzbank Elisabeth Andreae in a note.
South Africa is due hold general elections in mid-2019, with land and economic reforms seen as the main campaign issues.
Bonds weakened, with the yield on the benchmark paper due in 2026 up 6.5 basis points to 8.94 percent.
On the bourse, the all-share index strengthened 0.21 percent to 60,166 points and the Top-40 index 0.27 percent to 54,031 points, in line with international markets continuing to benefit from subdued trade tensions.
Shares in Steinhoff rose sharply after its board said it will meet over the next two days to discuss asset sales to boost cash flow and pay down debt. Its stock closed 25 percent higher at 2.75 rand.