South Africa's rand tumbled 2.5 percent to a two week low against the dollar on Thursday, falling quickly in the last hour of trading when stop losses were triggered above the 8.15 level by new complications over Europe's debt problems.

The rand steadily weakened during the session but was heavily and rapidly sold off once it breached key support at 8.15. It extended losses all the way to 8.27 and dealers said 8.35, the previous low, was not far off the cards.

We've had reports out of Europe that there hasn't been any progress in terms of a deal being formulated. The conference is going on, but they haven't made any headway in formulating a deal and that has caused a lot of panic in the market, said Paul Chakaduka of Global Trader.

By 1630 GMT the rand was at 8.2425, off Wednesday's 8.0380 close during the New York session.

Investors seemed unconvinced by efforts from European authorities to resolve that region's crisis soon.

Government bonds officially closed firmer on the Johannesburg Stock Exchange at around 1400 GMT when the day's trades are recorded, with locals seen picking up short to medium duration stock.

However prices followed the rand weaker after the official close as investors shied away from emerging market holdings.

The yield on the 2015 note added 3 basis points to 6.76 percent while that on the 2026 bond nudged up one basis point to 8.465 percent.

After the official close we lost about 4 to 5 points on the market, responding to this weaker rand in late trade. The break was about 8.15 on the currency, that's where a couple of long positions actually capitulated and liquidated, said Ashley Dickinson, bond trader at Renaissance BJM.