Embattled Public Enterprises Minister Lynne Brown on Tuesday told MPs she expected the boards of South Africa's corruption-stricken, cash-strapped parastatals to perform or be replaced.

"The message to the boards of all SOCs is that they must shape up or ship out. If they are unable to instill confidence in their management and oversight responsibilities, they will be rotated," Brown told Parliament's portfolio committee on public enterprises.

She added that the boards had been warned to mitigate any negative impact on their credit ratings, and indirectly on the sovereign rating.

The committee is conducting an inquiry into the use of state funds at Eskom to benefit the business empire of the Gupta family. Brown has denied any role in wrongdoing. The inquiry has since last year heard damning testimony on the Eskom board.

Brown reiterated that she wanted a probe by the Special Investigations Unit into the awarding of contracts at Eskom and Transnet to be fast-tracked.

"It will also throw up what are the general supply chain issues in the companies, particularly Eskom and Transnet."

She pleaded for procurement in Eskom to be decentralised to allow better oversight of the process.

She was quizzed on Tuesday by MPs on the reasons why state-owned companies were in disarray despite a raft of turnaround strategies and warned to ensure that they account to the legislature, following the failure of several to timeously submit full financial results to the committee.

"I would like us to come to an end with the poor attendance on the part of the state-owned enterprises to the committee," warned chairperson Lungi Mnganga-Gcabashe.

"We want to have an assurance from your office that when we sent invitation .... we do not want an excuse that your office did not inform them on time."

Brown replied that state-owned companies reported to Parliament directly.

"There is no excuse for it. The department just needs to push them along, but they have to be in attendance irrespective."