KPMG expects the results of an "independent investigation" into its auditing work for VBS Mutual Bank "imminently", it has told staff.
The investigation is being conducted by law firm Bowmans.
And the investigation may claim more heads, staff were warned.
"We anticipate further disciplinary action may be taken which may involve others," the audit firm said in an internal communication.
"We cannot tolerate any behaviour which places our people, our clients or the public at large, at risk."
The company promised to, in coming weeks, share with staff plans to define a future vision for KPMG "in which quality and integrity are at the forefront."
KPMG this week suspended Sipho Malaba, the partner who had signed off the accounts of VBS Mutual Bank until mid-2017.
Malaba had been put in charge of KPMG's biggest business unit as part of a reshuffle that had been aimed at restoring its credibility after it was shown to have missed – or turned a blind eye to – extraordinary accounting by companies linked to the Gupta family.
Several political parties accused it of facilitating state capture.
The tiny VBS shot to prominence after it extended a loan to then President Jacob Zuma to enable him to repay the state for taxpayer-funded work at his Nkandla homestead.
Around the same period VBS started to attract massive deposits from municipalities – despite the fact that it was unlawful for municipalities to keep money in a mutual rather than a full-fledged bank.
VBS was put into curatorship after it could not meet its obligations.
According to a report from the SA Reserve Bank (SARB), R900 million of the VBS deposits of R2.9 billion cannot be confirmed.