KPMG South Africa is reviewing work done by its partners in the wake of the resignation of two partners who faced disciplinary charges, its chief executive said on Sunday, another setback for the firm whose work is under scrutiny by authorities.

CEO Nhlamulo Dlomu said the resignation of partners Sipho Malaba and Dumi Tshuma on Friday after facing disciplinary charges over failure to disclose financial interests in VBS Mutual Bank, is a reminder of how much more needs to be done to "reaffirm the public's trust in KPMG".

She said the charges stemmed from the partners giving misleading information on loans they had from VBS.

Small lender VBS was in March placed under curatorship by the South African Reserve Bank because of liquidity issues.

"We will look at the last two years. We're looking at at least 200 files and looking at big, medium size and smaller clients," Dlomu told reporters.

"In essence what we're doing is we're opening ourselves up to proper and detailed scrutiny."

KPMG sacked its South African leadership in September last year after it found work done for companies owned by the Gupta family, a trio of businessmen with close ties to former President Jacob Zuma, "fell considerably short" of its standards. The Guptas have consistently denied wrong-doing.

The latest review will be in addition to other internal and external reviews that have been carried out since last September to date.

"The purpose of this new program is to assess the commitment to quality and professionalism of our engagement teams," KPMG said in a statement.

The company also said it has started an expanded process of integrity and background checks of all partners and their spouses, which will be coordinated by KPMG International.

Additional non-executives on the board will be appointed to ensure independent scrutiny, it said.

South Africa's companies registry office said in January it was pursuing criminal complaints against KPMG, as well as SAP and McKinsey, on suspicion that business they conducted with the Guptas broke the companies act.

A number of companies have since dropped KPMG as their auditor. Dlomu said clients who have dropped the firm are less than 10 percent of KPMG's client book.