The Zambian experience with nationalising the mines points to some of the risks, the ANC said in a discussion document placed on its website on Friday.

"Zambia nationalised the copper mines , which supplied 90% of its exports, in the early 1970s. It ended up hiring back  the multinational copper companies to manage them," the ANC said.

As international copper prices fell, the companies enjoyed guaranteed management fees while the state had to bear the losses to the mines, the ANC added.

The ANC Youth League's leader Julius Malema has repeatedly called for the nationalisation of SA's mines while President Jacob Zuma has made it clear that nationalisation was not on the cards.

However, the ruling party said debate on the nationalisation of mines was "vexed" by the fact that nationalisation took many different forms.

"We need to ensure that proposals become more specific about who  would end up owning the assets, who would manage them, and with what purpose, what would be the costs to the fiscus and the economy, and what would be the risks of failure as well as the benefits of success."

The nationalisation of mines will be discussed at the ANC's national general conference in September.