There is nowhere to hide for ANC bosses and government leaders who want to sabotage South Africa's migration from coal-powered fire stations to cleaner energy sources.

This has been made clear by the visit to the country of US Treasury Secretary Janet Yellen, who has gone far beyond the diplomatic parameters expected of a foreign diplomat.

She met with President Cyril Ramaphosa on Wednesday. On Thursday she had meetings with Finance Minister Enoch Godongwana and Energy Minister Gwede Mantashe.

Her biggest statement of intent was made on Thursday morning, when she walked into a meeting of the newly elected national executive committee of the ANC.

It's a diplomatic misstep that left party secretary general Fikile Mbalula with a public relations nightmare on his lap.

"I am here, I am telling you that it (Yellen's NEC visit) has nothing to do with our induction. So stop it with your conspiracies. The truth is -- to anybody who will want to say that the meeting was because the United States was briefing us on whatever -- there was nothing like that."

Yellen made it clear she was not in the country for small talk but to get on with the job.

"South Africa is the first country with a Just Energy Transition partnership to which the United States was proud to commit as a partner. This partnership represents SA's bold first step towards expanding electricity access and reliability and creating a low carbon and climate resilient economy. A move that I believe will alleviate the deep fiscal strain the energy sector is putting on South Africa's economy and support strong economic growth," she said of her meeting with the finance minister.

Her government has contributed over $1 billion to the $8.5 billion worth of pledges SA has received from the developed world to fund its Just Energy Transition Framework.

This is a tight balancing act, designed to ensure the country migrates to a low-carbon future without sacrificing jobs and turning coal mining towns into ghost towns.

Mantashe, who is seen as representing an anti-renewable energy lobby in the ruling ANC, said: "We agree to a transition from high- to low-carbon emissions. Our policy is that of mixed energy technologies to address energy poverty whilst transitioning to a low-carbon economy. Our Just Energy Transition must be people centred."

Next stop, Yellen will visit the Mpumalanga coal belt on Friday.