South Africa's economic recovery from the coronavirus crisis is likely to be "slow and difficult", deputy central bank governor Fundi Tshazibana said on Monday.

Speaking days after the central bank kept its main lending rate at 3.5%, after steep cuts earlier in the year, Tshazibana said the bank still had policy space but there were a number of risks looming over the medium-term.

"We haven't closed the door on anything," she told an emerging markets central banking conference organised by the Institute of International Finance.

One potential risk the central bank would monitor was volatility after recent credit rating downgrades, she said. Fitch and Moody's lowered South Africa's sovereign ratings deeper into sub-investment grade on Friday.

"This of course is what happens with ratings downgrades, so the further you go into 'junk' rating you would get a very different kind of investor, ... they might tend to be short-term," Tshazibana said.

She also said the fiscal environment was "quite challenging" and urged the government to implement reforms that had already been announced.

"Implementing is actually going to be the most important thing for us. ... We think that having credibility will come through implementing the reforms, rather than simply announcing the reforms," Tshazibana said.