South Africa’s foreign reserves rose in September, at a pace suggesting central bank intervention was not aggressive, despite strong gains in the local currency, a phenomenon some emerging markets have been fighting more actively.

The rand has gained more than 28 percent against the dollar, since the start of 2009, and more than 7 percent since the beginning of this year, prompting calls from labour unions for the authorities to step in more forcefully to weaken it.

The data showed the South Africa Reserve Bank’s intervention to curb currency appreciation remained “relatively benign” against more aggressive action by other central banks, said Razia Khan, regional head of research for Africa at Standard Chartered.

Net gold and foreign exchange reserves increased to $40.854 billion at the end of September from $39.178 billion in August, the central bank said in a statement posted on its website.