Finance Minister Pravin Gordhan is tackling the influential Gupta family head-on, pointedly snubbing President Jacob Zuma's friends.
He has pulled the plug on the Gupta-owned New Age newspaper's post-budget breakfast briefing, due to have taken place this week.
Ahead of what is expected to be South Africa's toughest austerity budget in decades, Gordhan's office has told The New Age of its decision, which bucks the trend of cabinet ministers meekly bowing to the Gupta family's demands.
The minister will also direct the National Treasury to scrutinise all coal-supply contracts awarded by Eskom, including those held by the Guptas.
Gordhan's moves further highlight the family's controversial relationship with the ANC, amid rumblings in the party and its trade union allies of "corporate capture" of the state by powerful business interests.
The breakfasts, broadcast by the SABC, have become a regular money-spinner for the newspaper and have served to underline the Gupta family's easy access to ministers and heads of state-owned enterprises.
Just last week, Zuma himself attended a New Age breakfast, after his state of the nation address .
The Sunday Times has learnt that Gordhan's office told the SABC he would appear at its breakfast briefing only if the Gupta-owned newspaper was not involved.
And although the Eskom coal-supply probe has a wide scope, sources say the Guptas are the main target.
"We are going to look at every contract there; especially those where the parastatal did not follow proper procurement processes," a senior Treasury source said.
Gupta-linked Tegeta Resources and Exploration is in the process of buying Optimum mine in Mpumalanga from mining conglomerate Glencore. It provides coal to Eskom's Arnot power station.
Gordhan's stance highlights a growing revolt within the ruling party against the perceived influence the Guptas have on Zuma and his cabinet.
It also comes amid moves within the ANC to distance its leaders from the Guptas.
New Age breakfast briefings have raked in millions of rands in sponsorships from state-owned entities, with companies such as Telkom and Transnet paying at least R1-million to sponsor the events.
There was an uproar in 2013 when it emerged that the office of the then Gauteng premier Nomvula Mokonyane paid nearly R700000 to speak at one of the events.
The New Age snub comes ahead of steps Gordhan is expected to unveil on Wednesday to drastically scale back on state spending, especially on luxuries and perks.
It felt like a good time to break with tradition and explore the other requests [to broadcast the briefing]
Gordhan declined to comment on his New Age breakfast decision, saying he had no time to worry about who would broadcast his post-budget briefing.
"You think I am going to spend my time four or five weeks after I am actually appointed worrying about which TV stations are involved and what breakfasts take place?" he said.
"I have no time for that. I only have time for working on the budget. So don't listen to gossip and don't try and create unnecessary sensation.
"The more important thing for the country is not this nonsense, it is whether we as a country can grow and create jobs. That's the key," he said.
His spokeswoman, Phumza Macanda, confirmed that the post-budget breakfast briefing would for the first time be broadcast on e.tv and eNCA.
"It felt like a good time to break with tradition and explore the other requests, a decision made easy by the compelling proposal that sees the minister reach a very wide audience that includes two community radio stations in Cape Town.
"We've never done that before so we're quite excited. SABC might not be broadcasting the event live but their reporters will still be able to cover the event," said Macanda.
Highly placed Treasury sources told the Sunday Times that the main reason Gordhan's breakfast briefing would not be shown on the SABC was the public broadcaster's perceived link with the Guptas.
The Sunday Times understands that the Treasury offered the briefing to the SABC, with the precondition that The New Age was not part of it, which the SABC refused, citing contractual obligations.
The move is said to have angered SABC chief operations officer Hlaudi Motsoeneng, who has requested a meeting with Gordhan and Treasury director-general Lungisa Fuzile.
"The matter has been elevated to us by our news team. I will only comment after meeting the minister," Motsoeneng said.
SABC spokesman Kaizer Kganyago said the broadcaster was confused by the decision.
"Actually, Treasury approached the SABC for this year's event, and we agreed to this with a clear understanding that it would be a partnership between the SABC and Treasury. We therefore do not know why they made the decision that they made."
eNCA national news editor Mapi Mhlangu said hosting the finance minister was a great opportunity for the channel. "[It should be] like in the US where there is a rotation of broadcasters. It is never the right of one broadcaster."
Gupta family spokesman Gary Naidoo said they had received a "very polite" message from Gordhan's office explaining that Treasury policy dictates that broadcasting access to the minister be shared.
"We totally respect and understand this position and look forward to welcoming Minister Gordhan back to a New Age event in the future," he said.
The Guptas' monopoly on post-budget breakfast briefings drew controversy three years ago when Gordhan offered the event to the Cape Chamber of Commerce. The organisation was strong-armed into sharing the platform with The New Age after the SABC refused to broadcast the event if the newspaper was not involved.
Access to New Age breakfast briefings usually costs those who attend over R700 a seat.
At the ANC' s national executive committee lekgotla last month, party leaders expressed their discomfort over the family's influence.
This week the ANC's top six officials summoned the family to its Luthuli House headquarters in Johannesburg to grill them about their business dealings following reports that they had strong-armed Glencore into selling them Optimum mine.
Insiders said ANC secretary-general Gwede Mantashe came under pressure to defend the integrity of the ANC by rapping the Gupta family over the knuckles and throwing Zuma under the bus.
However, Zuma and his ally, deputy secretary-general Jessie Duarte, were vehement in their assertion that the Gupta family had been unnecessarily attacked and needed to be protected. Mantashe, who has increasingly expressed frustration over the Gupta family's influence on some party leaders, was defeated, and the top six officials then opted to defend the family.
At a press conference on Thursday, Mantashe accused the South African media of being obsessed with the family.
At the time of going to press Treasury had not commented on the Eskom audits.