SACP general-secretary Blade Nzimande says the tripartite alliance must take responsibility for recent load shedding.
"The 1998 energy policy told us we needed to do certain things even in the early 2000s. We were told Eskom power stations must be maintained, must be renewed, we did not do that because we wanted to privatise.
It's our own failure that is leading to this load shedding," Nzimande said during his political report address at the SACP's special national congress.
South Africans took to social media to express anger and frustration over the current wave of load shedding.
With the country still gripped by stage 4 load shedding, Eskom announced it was shedding 6 000MW on Monday evening. This pushed South Africa to stage 6 for the first time since the forced blackouts began in 2008.
Many municipalities, including the City of Johannesburg, had no scheduling timetables for stage 6 and were caught off guard.
On Monday, President Cyril Ramaphosa, who has cut short his official trip to Egypt, said the "anger and frustration" over the power cuts were understandable.
"The extreme weather in several parts of the country over the last week has compounded the problems of an electricity grid that was already under great strain," he added.
Eskom earlier said heavy rains and floods at three power stations had caused its already reduced generation capacity to plunge further which forced it to institute stage 6 cuts to prevent a total collapse of the grid.
Speaking at the special national congress, Nzimande said the ANC-led alliance, which includes the SACP and Cosatu, should continue to fight against state capture and looting. He added he had confidence in the Ramaphosa administration.
However, he said the SACP was concerned that "[u]nder that banner of cleaning, there are people who are seeing an opportunity that because SAA was seen as corrupt, we must use this in order to buy SAA. That we cannot allow".
Nzimande added some of the ANC-led alliance's failures in managing state-owned enterprises (SOEs) was to "prescribe to them and say we will focus on our core service".
"Let's not fool ourselves. If we say SOEs must remain in the hands of the state, we must be clear what is to be done. We must say they must be in the hands of the state so that we could do A, B, C or D."