South Africa's reserves surge in one month

Analysts said that these figures implied that the central bank does not want a particularly strong currency.

It appears that much of the accumulation could have occurred in the April-May period when the rand broke through 7/dollar. In May, the governor of the central bank, Tito Mboweni, said that the rand might be "out of kilter" against the dollar, given the size of the country's external deficit.

South Africa's current account deficit stood at 7.8% of GDP in the last quarter of 2006.

In the past, observers have highlighted South Africa's relatively low level of foreign reserve holdings as a potential source of vulnerability. However, the growth in reserves over the 18 months has reduced these concerns.