This follows an exposé in the Sunday Times three weeks ago detailing how businessman Phosane Mngqibisa, who is said to be Pule's romantic partner, withdrew large sums of money soon after it was deposited into Bouwer's FNB bank account.

New details emerged this week of how Pule lobbied three companies regulated by her department - Vodacom, MTN and Telkom - to provide R25.7-million in "sponsorships" for the indaba organised by Carol Bouwer Productions. Pule's own department paid R10.5-million in sponsorship fees. In total, R36.2-million was raised.

Unbeknown to the telecoms companies, Mngqibisa was a second signatory to Bouwer's account - a potential conflict of interest, given his relationship to Pule. Now Telkom is considering launching its own forensic investigation into how its donation of R5.7-million was spent, and Vodacom is demanding answers from Bouwer.

Mngqibisa is close to a number of politicians, including Free State premier Ace Magashule. He repeatedly refused to answer questions from the Sunday Times. This week, he cited two deaths in his family for declining to respond.

Vodacom and Telkom confirmed this week they had demanded answers from Bouwer about what happened to the money for the event, which was attended by, among others, President Jacob Zuma and Deputy President Kgalema Mothlanthe.

Telkom spokesman Pynee Chetty said the company had "not received a satisfactory response as yet" from Bouwer.

"Carol Bouwer should deal with the inquiries regarding this matter transparently and expeditiously, failing which Telkom will have no choice but to appoint its own auditors," he said.

Vodacom corporate affairs chief Maya Makanjee said his company had also demanded "further information" from Bouwer "relating to the use of the sponsored amount", which was R5-million. Although MTN provided the largest amount, R15-million, it is taking no action.

MTN, which was accused this year of bribing politicians to get a cellular licence in Iran in 2005, said it was taking no action because it says it has no "competence" to trace the R15-million it gave.

Themba Nyathi, MTN SA human resources executive, said: "The allegations that came up [about] what transpired outside of MTN, that is something beyond MTN's competence.

"That is something that the Department of Communications will investigate through the auditor-general. We will wait for the outcome of the auditor-general's report."

The companies provided the sponsorship money after Pule sent letters to them "inviting" them to "cooperate with the Department of Communications and Carol Bouwer Productions" to ensure the indaba was a success.

Though the ICT Indaba, which was held in Cape Town, is believed to have raised more than R50-million in sponsorships and delegates' fees, experts say the cost of hosting the event was likely to be less than half that.

Fears that the scandal would be covered up escalated this week.

Cosatu general secretary Zwelinzima Vavi raised the issue of Mngqibisa's withdrawals at the union federation's 11th KwaZulu-Natal conference this week. Vavi reportedly said it was "disappointing" that ANC and government leaders ducked the issue, hoping "our people forget about [ allegations] in no time".

Cosatu has already called for a "thorough, independent investigation into the allegations", which it says highlights the danger of a government official having an arrangement with a private company run by a close friend or family member.

Although the matter is being probed by auditor-general Terence Nombembe, his office has no authority to delve into private-sector bank accounts such as that of Carol Bouwer Designs CC - the account into which most of the money was paid.

It has emerged that public protector Thuli Madonsela has turned down a request by the DA to probe the scandal because of "resource constraints" in her office.

"I have decided to suspend proceedings and allow the auditor-general's process to run its course," Madonsela said in a letter to DA MP Marian Shinn.

Pule refused to answer nine detailed questions from the Sunday Times, including about her relationship to Mngqibisa, saying only that "the auditor-general is looking into the matter [and] the department is awaiting a report in this regard".

Pule's spokesman, Siya Qoza, said the auditor-general's investigation would be finalised in about two weeks. "At this point, all we can say is we have not received any feedback from the auditor-general or Carol Bouwer (sic)."

Mngqibisa refused to clarify his relationship with Pule, reiterating his statement that "I prefer to keep my private personal life private".

Shinn said: "It is telling that Dina Pule has chosen not to clarify the nature of her relationship with [Mngqibisa]. The public deserves to know whether there was a conflict of interest in him having rights to the sponsorship money."

Shinn said the worry is that the auditor-general probe could be a smoke screen, as Nombembe "can't follow the money in private entities' accounts. He can just check whether the proper processes were followed with the department's R10-million, but not what happened to the cellphone companies' money," she said.

After the Sunday Times exposed how Mngqibisa withdrew cash from that account, Bouwer wrote a letter to all three companies and Pule's department, claiming she had no idea about Pule's relationship to Mngqibisa.

Bouwer's letter confirms that she gave Mngqibisa "the responsibility to be the secondary user on the ICT Indaba account due to our shared responsibility on the project". She added: "I certainly did not have any know-ledge and in fact, still do not have knowledge of wrongdoing or misappropriation of funds on the part of Mngqibisa."

When asked again how much money he withdrew and why, Mngqibisa refused to answer questions, saying: "Please seek information about the accounts of Carol Bouwer Productions from [her]."

Bouwer told the Sunday Times that she had nothing more to say on the subject.

A number of questions remain unanswered, including why MTN paid its R15-million sponsorship fee into the account of a company called ABR Consulting - a Woodmead-based company with virtually no track record - rather than that of Bouwer.

MTN's Nyathi said this was because the Bouwer account "did not have a tax clearance certificate", so they paid this money into an "alternative account".

MTN's explanation is contradicted by Vodacom. Maya Makanjee, Vodacom corporate affairs chief, said: "A full due diligence was performed ... we also obtained a tax clearance certificate in relation to the entity, being Carol Bouwer Designs cc."