The Special Investigating Unit (SIU) has said its investigation into the Department of Health's contract with Digital Vibes is "at an advanced stage".

Speaking at a briefing held by the South African National Editors' Forum (Sanef) on Thursday, SIU head advocate Andy Mothibi said an announcement would be made in the next couple of weeks.

Mothibi said "the investigation team has made some findings but can't disclose the details as yet."

But he said the SIU was going through all the payments and invoices related to the R159-million contract so that it could stop payments where necessary.

He said the SIU didn't want to "cut corners" but wanted to ensure that the findings were backed by "solid evidence".

Earlier this week, the Daily Maverick reported that the health department granted a tender to a company, whose officials have close personal links to Health Minister Zweli Mkhize, to do work the department's communications team could have done.

On Wednesday, Mkhize said the department's investigation found that the tender bidding process followed was in contravention of the Public Finance Management Act.

Mothibi said the SIU was working with the Fusion Centre to follow the "money flow".

Mothibi said the investigation was looking at "quite a number" of private individuals and companies, but he was "constrained at the moment" in terms of talking about it.

There is also "quite a number of officials" that the SIU would be referring for disciplinary action.

He said if evidence of fraud or corruption was found, the SIU would look at recovering all the money spent on the contract, but if there were irregularities, the SIU would establish what losses the state had suffered and would focus on recovering it.

To date, the SIU has finalised investigations into 1 071 Covid-19-related contracts worth R5.7-billion and involving 19 835 service providers.

Investigations into 1 084 contracts worth R7.6-billion, involving 2 695 service providers, were ongoing, while investigations into 332 service providers have yet to commence.

Mothibi said the SIU was hoping to complete these by August, but the unit was also "constantly" getting in new investigations.

In the case of the Gauteng education department's R431-million contract for deep cleaning schools, Mothibi announced that the Special Tribunal had granted a preservation order worth R40.7-million to the SIU to freeze the bank accounts and assets of 14 service providers.

Mothibi said in the 2019-'20 financial year, contracts worth R4.3-billion had been set aside or declared invalid as a result of SIU investigations, R346-million in state money was recovered and losses of R400-million prevented.

A total of 638 officials were referred for disciplinary action.