President Jacob Zuma won't "jump to conclusions" on allegations that Communications Minister Siphiwe Nyanda has benefited from tenders awarded by his department.

"There are allegations, I am sure there are processes that happen if there are allegations," Zuma said at a press conference in Pretoria on Thursday.

"I don't think we should jump to conclusions before any investigation is done. I think it would be totally out of order.

"If there are allegations, these allegations need to be substantiated."

In March, freight group Transnet dismissed two senior managers for irregularly awarding a R55-million tender to a company allegedly linked to Nyanda.

"The contract in question was awarded in a confined process - meaning without an open tender process being conducted or other qualifying bidders being invited - and without following the required governance processes," a Transnet statement read at the time.

In a separate case, the Democratic Alliance (DA) alleged that a company partly owned by Nyanda was unlawfully awarded a R67,8-million tender by the Gauteng roads and transport department.

Earlier this year Nyanda was accused of indulging in a "caviar and silk" lifestyle after allegedly spending thousands of rands on hotel stays at the luxurious Mount Nelson and Twelve Apostles hotels and buying two R1,2-million BMWs for his work.

Congress of South African Trade Unions (Cosatu) leader Zwelinzima Vavi singled out Nyanda when criticising the government's failure to act on allegations of corruption in Cabinet.

Vavi had said reports that Nyanda had spent R500 000 on hotels in Cape Town should be probed.

Recently Nyanda had reportedly been embroiled in a bitter fight with his director-general Mamodupi Mohlala, who had refused to sign off on the minister's tenders.

Nyanda rejected reports that he was set to suspend Mohlala as "false, spurious and malicious".

His spokesperson Tiyani Rikhotso said that Nyanda exercised political oversight over the department and gave it policy direction in line with his statutory and constitutional mandate.

He also respected the legal prescripts defining the scope, nature and extent of his responsibilities and was not involved in issuing or adjudication of tenders, which were the responsibility of the department's management.

Business Day reported last Thursday that Nyanda was expected to suspend Mohlala following repeated disagreements over tenders she refused to sign.

It was understood that Mohlala warned Nyanda this week that removing the administration of tenders from her would violate the Public Finance Management Act.

Last Monday, Nyanda instructed that all tenders for the department be cancelled until they had been "discussed and approved by the minister".

Business Day reported that he also changed Mohlala's job description, effectively stripping her of some powers, including the administering of tenders, for which she was responsible as accounting officer.

DA Member of Parliament Niekie van den Berg said that he would write to the Public Protector to ask for an investigation into all State tenders awarded to Nyanda.

"This latest incident is just another in a long list of tender scandals that the minister has been embroiled in and it is has now become necessary that all tenders involving companies linked to the minister be investigated in order to determine whether there were any other irregularities in their awarding.

United Democratic Movement leader Bantu Holomisa said that his party was perturbed by the reports.

"What is even more disturbing is that the reported source of the conflict between the minister and the DG relates to undue ministerial interference in State tenders to favour people linked to the minister," he said.

But Zuma said that the allegations against Nyanda were nothing new and came from "faceless" sources.

"These allegations are not old. They have just been made and are still current.

"In the first instance, these allegations come from newspapers. Newspapers have sources that are faceless.

"If we look at the allegations. If you read your newspaper that says things, you don't even know where to start.

"The allegations just come. Once they come we have to look at it and there are different ways of doing so."

Zuma admitted however, that he had heard from Nyanda of a "problem" with the director-general.

"What is clear is the issue between the minister and the director-general. The minister in passing indicated there is a problem. He has not given a proper and formal report.

"Once this happens we move in."